Commonwealth v. Privette

NOTICE: All slip opinions and orders are subject to formal
revision and are superseded by the advance sheets and bound
volumes of the Official Reports. If you find a typographical
error or other formal error, please notify the Reporter of
Decisions, Supreme Judicial Court, John Adams Courthouse, 1
Pemberton Square, Suite 2500, Boston, MA, 02108-1750; (617) 557-
1030; SJCReporter@sjc.state.ma.us

SJC-13248

COMMONWEALTH vs. DAVID PRIVETTE.

Suffolk. September 9, 2022. - March 28, 2023.

Present: Budd, C.J., Gaziano, Lowy, Cypher, Kafker, Wendlandt,
& Georges, JJ.

Firearms. Practice, Criminal, Motion to suppress, Interlocutory
appeal. Evidence, State of police knowledge.
Constitutional Law, Search and seizure, Reasonable
suspicion, Investigatory stop. Search and Seizure,
Reasonable suspicion, Threshold police inquiry. Threshold
Police Inquiry.

Indictments found and returned in the Superior Court
Department on October 10, 2018.

A pretrial motion to suppress evidence was heard by Elaine
M. Buckley, J.

An application for leave to prosecute an interlocutory
appeal was allowed by Lenk, J., in the Supreme Judicial Court
for the county of Suffolk, and the appeal was reported by her to
the Appeals Court. After review by the Appeals Court, the
Supreme Judicial Court granted leave to obtain further appellate
review.

Anne Rousseve, Committee for Public Counsel Services, for
the defendant.
Kathryn Sherman, Assistant District Attorney, for the
Commonwealth.
 2

GAZIANO, J. On a rainy, early morning in August of 2018,

Boston police officers received a report of an armed robbery of

a gasoline station in the Clam Point area of the Dorchester

section of Boston at 3:35 A.M. The first radio report described

the suspect as a "Black male, late twenties, five foot seven,

blue hoodie, blue jeans, on foot towards [a pharmacy]." Later

dispatches added that the suspect had facial hair. Seven

minutes after the first dispatch, and one street away from the

location of the armed robbery, an officer stopped the defendant.

Contemporaneously, other officers responding to the call were

canvassing the area for potential suspects; one of the officers

continued to communicate via the police department radio channel

dedicated to use in the area. This officer arrived at the

location of the investigatory stop at the same time as the

officer who initiated the stop. After a patfrisk of the

defendant's person and his backpack by both officers revealed

$432 and a firearm, the defendant was arrested and indicted for

multiple firearms offenses. He filed a motion to suppress the

items seized as a result of the stop, on the ground that the

officer who initiated it lacked the requisite reasonable

suspicion. After an evidentiary hearing, a Superior Court judge

denied the motion, and the defendant sought interlocutory

review. The single justice allowed the appeal to proceed in the
 3

Appeals Court, where the court affirmed the denial of the motion

to suppress. We then allowed the defendant's application for

further appellate review.

We are tasked with deciding whether, through the collective

knowledge doctrine, information known to other investigating

officers may be imputed to the officer who initiated the stop,

and thus be included in the calculus of reasonable suspicion

without violating art. 14 of the Massachusetts Declaration of

Rights. To date, we have permitted the aggregation of

information known to one police officer to other officers for

consideration in the calculus of reasonable suspicion or

probable cause, even without evidence of communication among the

officers, so long as they were engaged in a cooperative effort.

See, e.g., Commonwealth v. Mendez, 476 Mass. 512, 519 n.8 (2017)

(trooper's knowledge that defendant was suspect in shooting was

imputed to other arresting officer, even absent evidence of

direct communication between officers), citing Commonwealth v.

Quinn, 68 Mass. App. Ct. 476, 480-481 (2007), quoting

Commonwealth v. Riggins, 366 Mass. 81, 88 (1974) ("Where a

cooperative effort is involved, facts within the knowledge of

one police officer have been relied on to justify the conduct of

another"); Commonwealth v. Montoya, 464 Mass. 566, 576 (2013)

(imputing one officer's knowledge that individual just purchased

drugs to acting officer absent communication); Commonwealth v.
 4

Roland R., 448 Mass. 278, 285 (2007) ("the knowledge of each

officer is treated as the common knowledge of all officers"

[citation omitted]).

We conclude that, with respect to the horizontal collective

knowledge doctrine, art. 14 requires more. To be consistent

with the requirements of art. 14, in order to aggregate

officers' knowledge, the officers must be involved in a joint

investigation, pursuing a mutual purpose and objective, and they

must be in close and continuous communication with each other

about that shared objective. While the officer who actually

effectuates the stop need not have personal knowledge of all of

the officers' pooled knowledge giving rise to reasonable

suspicion or probable cause, the officer must be aware of at

least some of the critical facts and must have been in

communication with others who have such knowledge.

In the circumstances here, some, but not all, of the other

investigating officers' knowledge can be imputed to the acting

officer. We conclude that, with or without this imputed

knowledge, the officer who stopped the defendant had reasonable

suspicion to do so.

1. Background. a. Facts. We summarize the relevant

facts concerning the stop from the motion judge's findings,

supplemented by uncontroverted and undisputed facts from the

record that have been credited by the motion judge, leaving
 5

certain details for later discussion. See Commonwealth v.

Jones-Pannell, 472 Mass. 429, 431 (2015). Three Boston police

officers testified at the evidentiary hearing on the motion to

suppress: Officer Brian Doherty, Lieutenant Darrell Dwan,1 and

Officer Luis Lopez. The motion judge found each testifying

officer credible without qualification.

On August 12, 2018, Doherty, who was assigned to the police

department's C-11 district, was working the midnight shift and

covering the Clam Point area of Dorchester. He was in plain

clothes and driving an unmarked vehicle. At approximately

3:35 A.M., Doherty received a police department radio

transmission over channel six2 reporting that there had been an

armed robbery at a gasoline station on Morrissey Boulevard. The

dispatcher thereafter transmitted a description of the suspect

as "Black male, late twenties, five foot seven, blue hoodie,

blue jeans, on foot towards [a pharmacy]." In the first

dispatch, there was no mention of the suspect having facial

hair.

Officers continued to communicate via channel six. Dwan,

who was canvassing the surrounding streets, reported at

1 At the time of the robbery, Dwan held the rank of
sergeant.

2 Channel six is the dedicated police channel for the C-11
area and is transmitted to the entire district.
 6

3:37 A.M. that no one was present on his part of Morrissey

Boulevard.3 Over the course of the next seven minutes, the

dispatcher transmitted two additional descriptions of the

suspect over channel six. A second transmission was broadcast

at 3:38 A.M. and described the suspect as being "a Black male,

twenty-eight, twenty-nine, medium build, five foot seven, five

foot eight, blue hoodie, blue jeans, with facial hair, silver

firearm." The final description was dispatched at 3:41 A.M.,

and described the suspect as a "Black male, twenty-eight,

twenty-nine, medium build, five foot seven, five foot eight,

blue hoodie, blue jeans, some facial hair."4

In response to the dispatched report of the armed robbery,

Doherty headed toward the area near the pharmacy from the police

station where he had been working. At that time, Doherty had

been a Boston police officer for four years and had been working

in Clam Point for two years. He also had grown up a few blocks

away from the scene of the robbery. Doherty was aware of a

large gap in a fence that separated Morrissey Boulevard and

Ashland Street not far from the scene. As he was responding to

the dispatch, Doherty drove through approximately nine streets

3 Dwan confirmed via channel six that no one was present on
Morrissey Boulevard. The recordings of the dispatches, which
were introduced in evidence, support this testimony.

4 Dwan testified that he heard updated descriptions of the
suspect and that he knew the suspect had facial hair.
 7

without seeing anyone else outside; he was monitoring channel

six while driving. Seven minutes after the robbery, Doherty

came across the defendant on Ashland Street.

When Doherty saw the defendant at 3:41 A.M., it was raining

and dark. Doherty observed that the individual walking toward

him was a Black male with facial hair, wearing a green sweater

and black jeans, and of the same approximate age as the

broadcast description. At the time of the encounter, the

defendant was five feet, eleven inches tall and thirty-two years

old. Doherty pulled over and parked, identified himself as

"Boston Police," and told the defendant to "show me your hands."

The defendant complied; he made no attempt to run or to evade

the officer. Doherty then conducted a patfrisk of the defendant

and felt a large wad in the defendant's pocket. Doherty

instructed the defendant to remove what was in his pocket, which

turned out to be $432. No weapons were recovered from the

defendant's person.

Dwan arrived at the corner of Ashland Street and Everdean

Street, from the opposite direction, at the same time that

Doherty reached that location. As Dwan approached the defendant

from behind, he saw that the defendant was wearing a red plaid

backpack. Dwan pat frisked the backpack, without opening it,

and felt a hard object near the top. Upon opening the backpack,

Dwan saw a silver gun.
 8

Lopez also was on duty on the night of the robbery. In

response to the communications on channel six, Lopez drove

around the surrounding Clam Point neighborhood, focusing his

efforts on Victory Road and the area near the pharmacy. Nothing

in the record indicates that Lopez communicated with anyone

during his surveillance, nor that he was involved in the stop of

the defendant. After observing no one in the area, Lopez

transported the victim to the scene of the stop for a showup

identification. Following a positive identification by the

victim, the defendant was arrested.

b. Procedural background. On October 10, 2018, a grand

jury returned indictments charging the defendant with five

firearms offenses.5 He filed a motion to suppress the evidence

obtained as a result of the stop, the patfrisk of his person,

and the patfrisk of his backpack. He also moved to suppress the

subsequent showup identification. Following an evidentiary

hearing, a Superior Court judge denied the defendant's motion.

In her findings, the motion judge reasoned that Doherty had

had adequate reasonable suspicion to conduct the investigatory

stop based on the defendant's presence "in the locus of the

5 The charges included armed robbery, G. L. c. 265, § 17;
possession of a firearm during the commission of a felony, G. L.
c. 265, § 18B; possession of a firearm as an armed career
criminal, G. L. c. 269, §§ 10 (a), 10G (b); possession of
ammunition without a firearm identification card, G. L. c. 269,
§ 10 (h); and carrying a loaded firearm, G. L. c. 269, § 10 (n).
 9

robbery and within minutes of its occurrence." She also

considered the early morning hour, the fact that the defendant

was the only person observed in the area, and the fact that he

fit the general description that was broadcast on channel six.

The defendant filed an application for leave to pursue an

interlocutory appeal in the county court pursuant to Mass. R.

Crim. P. 15 (a) (2), as amended, 476 Mass. 1501 (2017). The

single justice allowed the application and ordered the appeal to

proceed in the Appeals Court. The Appeals Court affirmed the

denial of the motion to suppress. See Commonwealth v. Privette,

100 Mass. App. Ct. 222, 222-223 (2021). In its calculus of

reasonable suspicion, the Appeals Court supplemented the motion

judge's findings by imputing to Doherty Dwan's knowledge that

the suspect had a beard and that Dwan saw no one walking in the

area of Morrissey Boulevard or Victory Road. Id. at 228. The

Appeals Court also imputed to Doherty Lopez's knowledge that no

one had been present in the area of Victory Road. Id. In

affirming the denial of the motion to suppress, the Appeals

Court held that the defendant's appearance, his proximity to the

scene, and the fact that he was the only person outside in the

surrounding area all supported a determination that there was

reasonable suspicion. Id. at 231-233. We granted the

defendant's application for further appellate review.
 10

2. Discussion. On appeal, the defendant challenges only

the validity of the stop. He does not challenge the patfrisk of

his person or his backpack, nor does he challenge the

identification procedure. Thus, the narrow question before us

is whether the investigatory stop was constitutionally

permissible.

a. Standard of review. In reviewing a ruling on a motion

to suppress, we accept the motion judge's findings of fact

absent clear error. Commonwealth v. Tremblay, 480 Mass. 645,

652 (2018). We conduct an independent review of the judge's

application of constitutional principles to the facts found.

Commonwealth v. Mercado, 422 Mass. 367, 369 (1996).

b. Reasonable suspicion. Article 14 provides that

"[e]very subject has a right to be secure from all unreasonable

searches, and seizures, of his person." To justify an

investigatory stop under art. 14, a police officer must have

reasonable suspicion that the person stopped has committed, is

committing, or is about to commit a crime. Commonwealth v.

Costa, 448 Mass. 510, 514 (2007). The reasonable suspicion

analysis examines "the totality of the facts on which the

seizure is based." Commonwealth v. Meneus, 476 Mass. 231, 235

(2017). Reasonable suspicion "must be based on specific and

articulable facts, and reasonable inferences therefrom, in light

of the officer's experience" (citation omitted). Commonwealth
 11

v. Gomes, 453 Mass. 506, 511 (2009). See Terry v. Ohio, 392

U.S. 1, 21 (1968). Reasonable suspicion also must be more than

a hunch. Commonwealth v. Lyons, 409 Mass. 16, 19 (1990).

As an initial matter, the motion judge found, and the

parties agree, that the defendant was seized when Doherty

announced to him, "Boston Police," and told him to "show me your

hands." The question before us is whether Doherty had

reasonable suspicion to justify the stop. This, in turn,

implicates the narrow legal issue whether Dwan's and Lopez's

knowledge and observations that night may be imputed to Doherty,

under the collective knowledge doctrine.

i. Collective knowledge doctrine. The collective

knowledge doctrine, sometimes referred to as the fellow officer

rule, originated in Williams v. United States, 308 F.2d 326, 327

(D.C. Cir. 1962), where the United States Court of Appeals for

the District of Columbia Circuit rejected a defendant's

assertion that the arresting officer was required to have had

firsthand information in order to make an arrest. The court

concluded that "the collective knowledge of the organization as

a whole can be imputed to an individual officer when he is

requested or authorized by superiors or associates to make an

arrest." Id. The United States Supreme Court subsequently

adopted the doctrine. See Whiteley v. Warden, Wyo. State

Penitentiary, 401 U.S. 560, 568 (1971). The Court initially
 12

concluded that "[c]ertainly police officers called upon to aid

other officers in executing arrest warrants are entitled to

assume that the officers requesting aid offered the magistrate

the information requisite to support an independent judicial

assessment of probable cause." See id. The Court later held

that, in forming reasonable suspicion for an investigatory stop,

officers could rely on a police bulletin issued by another

police department, even though the acting officers were not

"themselves aware of the specific facts which led their

colleagues to seek their assistance." See United States v.

Hensley, 469 U.S. 221, 231 (1985).

More recently, the collective knowledge doctrine has

evolved into two different types: horizontal collective

knowledge and vertical collective knowledge. Each is used in

determining the existence of reasonable suspicion and probable

cause. See United States v. Massenburg, 654 F.3d 480, 495-496

(4th Cir. 2011) (distinguishing between horizontal and vertical

collective knowledge and analyzing collective knowledge doctrine

as it applies to reasonable suspicion); United States v. Chavez,

534 F.3d 1338, 1345 (10th Cir. 2008), cert. denied, 555 U.S.

1121 (2009) (analyzing probable cause based on collective

knowledge).

Vertical collective knowledge, the original version of the

doctrine, involves one officer directing or requesting another
 13

officer to conduct a stop, frisk, search, or an arrest. Courts

review the validity of the intrusion based on the directing

officer's knowledge. See Massenburg, 654 F.3d at 493 ("the

collective-knowledge doctrine simply directs us to substitute

the knowledge of the instructing officer or officers for the

knowledge of the acting officer"). In this context, it is not

necessary for the acting officers to have personal knowledge of

the facts establishing reasonable suspicion or probable cause,

because the acting officers "are acting as the agents or proxies

of, or are relying on information provided by, the officers who

possess probable cause or reasonable suspicion." United States

v. Gorham, 317 F. Supp. 3d 459, 473 (D.D.C. 2018).

The horizontal knowledge doctrine, by contrast, permits the

aggregation of information known to multiple officers; no one

officer need have sufficient information to support probable

cause or reasonable suspicion. Instead, "a number of individual

law enforcement officers have pieces of the probable cause

puzzle" that are aggregated to meet the threshold. See Chavez,

534 F.3d at 1345. Under the horizontal collective knowledge

doctrine, officers are not acting at the direction of another,

as they would be under the vertical collective knowledge

doctrine. See Commonwealth v. Yong, 644 Pa. 613, 636, cert.

denied, 139 S. Ct. 374 (2018) (doctrine of horizontal collective
 14

knowledge is one in which "the arresting officer does not have

the requisite knowledge and was not directed to so act").

Reliance upon vertical collective knowledge has sparked

little controversy and is supported by the United States Supreme

Court's decision in Hensley, 469 U.S. at 231 ("this rule is a

matter of common sense"). By contrast, both Federal and State

courts are split over how broadly to apply the horizontal

outgrowth of the collective knowledge doctrine, the question at

issue here. Moreover, further complicating the issue,

notwithstanding the evolution of the doctrine into these two

distinct approaches, not all fact patterns will necessarily fall

squarely within either the vertical or horizontal framework.

See Yong, 644 Pa. at 636, citing Chavez, 534 F.3d at 1345 n.12.

At this point, those courts to have addressed the question

of horizontal collective knowledge have required communication

between officers prior to an intrusion, a joint cooperative

effort, close physical proximity, or some combination thereof.

See, e.g., Grassi v. People, 2014 CO 12, ¶ 1, cert. denied, 574

U.S. 1014 (allowing imputation of collective knowledge to

officer only if "(1) that officer acts pursuant to a coordinated

investigation and (2) the police possess the information at the

time of the search or arrest"). To date, courts have developed

at least three variations of the horizontal collective knowledge

doctrine.
 15

The United States Courts of Appeals for the Second, Fourth,

and Tenth Circuits, and a plurality of the States6 to have

addressed the issue, have required evidence that the actual

facts underlying the analysis of reasonable suspicion or

probable cause be communicated to the acting officer prior to

the stop, frisk, search, or arrest. See, e.g., United States v.

Hussain, 835 F.3d 307, 316 n.8 (2d Cir. 2016).

The United States Court of Appeals for the Fourth Circuit

discussed this approach in some detail in Massenburg, 654 F.3d

at 491-496. The court noted concerns about the effect that

after-the-fact aggregation of information would have on the

exclusionary rule. "Because it jettisons the present

requirement of communication between an instructing and an

acting officer, officers would have no way of knowing before a

6 See People v. Chalak, 48 Cal. App. 5th Supp. 14, 20
(2020); State v. Cooley, 457 A.2d 352, 353 (Del. 1983); Montes-
Valeton v. State, 216 So. 3d 475, 479 (Fla. 2017); State v.
Fischer, 230 Ga. App. 613, 614 (1998), overruled on other
grounds by Workman v. State, 235 Ga. App. 800, 803 (1998); State
v. Barnes, 58 Haw. 333, 336-337 (1977); State v. Amstutz, 169
Idaho 144, 148 (2021); People v. Creach, 69 Ill. App. 3d 874,
882 (1979); State v. M.J.M., 837 N.E.2d 223, 226 (Ind. Ct. App.
2005); State v. Miller, 49 Kan. App. 2d 491, 497 (2013); State
vs. Giannini, N.M. Ct. App., No. 34,199, slip op. at 5 (July 20,
2016); State v. Battle, 109 N.C. App. 367, 371 (1993); State v.
Rahier, 2014 ND 153, ¶ 15; State v. Ojezua, 2016-Ohio-2659, ¶¶
38-40 (App. Ct.); State v. Mickelson, 18 Or. App. 647, 650
(1974); State v. Mohr, 2013 S.D. 94, ¶ 18; State v. Echols, 382
S.W.3d 266, 278 (Tenn. 2012); McArthur v. Commonwealth, 72 Va.
App. 352, 365 (2020); Guandong v. State, 2022 WY 83, ¶¶ 19-20.
 16

search or seizure whether the aggregation rule would make it

legal, or even how likely that is." Id. at 494. Jurisdictions

adopting this approach have explained that the deterrent effect

of the exclusionary rule would be greatly limited without a

requirement of communication; the absence of such a requirement

could create incentives for officers to conduct illegal searches

and seizures, knowing that there was no reasonable suspicion or

probable cause, on the slim chance that someone else on the team

had had the requisite information. See id. ("Perhaps an officer

who knows she lacks cause for a search will be more likely to

roll the dice and conduct the search anyway, in the hopes that

uncommunicated information existed"). See McArthur v.

Commonwealth, 72 Va. App. 352, 365 (2020) (citing similar

concerns that "the legality of a warrantless search would depend

solely on whether officers [were] able to gather information

held by other officers, after-the-fact, to create reasonable

suspicion or probable cause").

Another concern that has been mentioned with the

aggregation of uncommunicated information is that it could

reward police officers who were acting in bad faith; for

example, investigatory teams invariably could find sufficient

probable cause or reasonable suspicion based on information that

had been learned after the stop. See Gorham, 317 F. Supp. 3d

at 473, citing Massenburg, 654 F.3d at 494. For these reasons,
 17

jurisdictions that limit the horizontal collective knowledge

doctrine require communication of the pertinent information

prior to permitting it to be factored into the calculus of

reasonable suspicion or probable cause. See, e.g., Chavez, 534

F.3d at 1345, citing United States v. Shareef, 100 F.3d 1491,

1504 (10th Cir. 1996) ("In such situations, the court must

consider whether the individual officers have communicated the

information they possess individually, thereby pooling their

collective knowledge to meet the probable cause threshold");

State v. M.J.M., 837 N.E.2d 223, 226 (Ind. Ct. App. 2005) ("In

order to rely on collective knowledge, the knowledge sufficient

for reasonable suspicion must be conveyed to the investigating

officer before the stop is made").

Following a decision by the United States Court of Appeals

for the Fifth Circuit, see United States v. Ragsdale, 470 F.2d

24, 30 (5th Cir. 1972), a small number of jurisdictions have

adopted an exception to the requirement that the acting officer

act with awareness of the other officers' knowledge, sometimes

known as the inevitable discovery exception, see 2 W.R. LaFave,

Search & Seizure § 3.5(c), at 351-352 (6th ed. 2020). See,

e.g., Hurlburt v. State, 425 P.3d 189, 194-195 (Alaska Ct. App.

2018) (adopting inevitability exception in analysis of

reasonable suspicion in case involving driving under influence);

State v. Ochoa, 131 Ariz. 175, 178 (Ariz. Ct. App. 1981)
 18

(declining to hold intrusion was unconstitutional "simply

because a member of the team having less knowledge than the

others moved too quickly and did what the more knowledgeable

members of the team would imminently and lawfully have done");

Smith v. State, 719 So. 2d 1018, 1023 (Fla. Dist. Ct. App. 1998)

("when the officer who does possess the probable cause is in a

close time-space proximity, evidence of a direct communications

link between the officers is not necessarily required"); Yong,

644 Pa. at 636 ("we hold the seizure is still constitutional

where the investigating officer with probable cause or

reasonable suspicion was working with the officer and would have

inevitably and imminently ordered that the seizure be

effectuated").

The second approach to the horizontal collective knowledge

doctrine requires communication amongst officers to establish

that they are engaged in a joint effort, even though explicit

communication of the underlying facts supporting reasonable

suspicion or probable cause is not necessary. To date, a

plurality of United States Courts of Appeals, and a handful of

States, have permitted aggregation, so long as there is evidence

of some communication between the officers involved in the

investigation; relaying the specific facts that provided the

basis for reasonable suspicion or probable cause generally has

not been required. See United States v. Ramirez, 473 F.3d 1026,
 19

1032, 1037 (9th Cir. 2007). See, e.g., State v. Breeding, 200

So. 3d 1193, 1200 (Ala. Crim. App. 2015), quoting United States

v. Esle, 743 F.2d 1465, 1476 (11th Cir. 1984), overruled on

other grounds by United States v. Blankenship, 382 F.3d 1110,

1122 n.23 (11th Cir. 2004) ("[I]t is a 'well-recognized

principle that, where a group of officers is conducting an

operation and there is at least minimal communication among

them, [the appropriate course is to] look to the collective

knowledge of the officers in determining probable cause'").

For instance, the United States Court of Appeals for the

Fifth Circuit has held that "probable cause can rest upon the

collective knowledge of the police, rather than solely on that

of the officer who actually makes the arrest, when there is some

degree of communication between" those officers (quotations and

citation omitted). United States v. Kye Soo Lee, 962 F.2d 430,

435 (5th Cir. 1992), cert. denied, 506 U.S. 1083 (1993). See

United States v. Ibarra, 493 F.3d 526, 530 (5th Cir. 2007)

("Under the collective knowledge doctrine, it is not necessary

for the arresting officer to know all of the facts amounting to

probable cause, as long as there is some degree of communication

between the arresting officer and an officer who has knowledge

of all the necessary facts"). The United States Court of

Appeals for the Sixth Circuit permits the knowledge of a group

of officers to "be considered in determining probable cause, not
 20

just the knowledge of the individual who physically effected the

arrest," so long as the "agents [were] in close communication

with one another." United States v. Blair, 524 F.3d 740, 752

(6th Cir. 2008), quoting United States v. Woods, 544 F.2d 242,

260 (6th Cir. 1976). Otherwise put, the requirement of

communication "serves to distinguish between officers

functioning as a 'search team,' and officers acting as

independent actors who merely happen to be investigating the

same subject" (citation omitted). United States v. Gillette,

245 F.3d 1032, 1034 (8th Cir.), cert. denied, 534 U.S. 982

(2001).

Finally, the minority view, which has been adopted by the

United States Courts of Appeals for the First and Third

Circuits, and a handful of States (including, to date,

Massachusetts), has allowed information to be aggregated amongst

officers even absent evidence of any sort of communication

between them. See, e.g., United States v. Cruz-Rivera, 14 F.4th

32, 44 (1st Cir. 2021), cert. denied, 142 S. Ct. 1456 (2022),

quoting United States v. Azor, 881 F.3d 1, 8 (1st Cir. 2017)

("we 'look to the collective information known to the law

enforcement officers participating in the investigation rather

than isolat[ing] the information known by the individual

arresting officer'"); United States v. Whitfield, 634 F.3d 741,

746 (3d Cir. 2010) ("it would be impractical to expect an
 21

officer in such a situation to communicate to the other officers

every fact that could be pertinent in a subsequent reasonable

suspicion analysis"); State v. Goff, 129 S.W.3d 857, 863 (Mo.

2004) (declining to require specific communication between

officers in order to aggregate information in making

determination of reasonable suspicion or probable cause). See

also Mendez, 476 Mass. at 519 n.8 (imputing uncommunicated

knowledge from one officer to another in calculus of reasonable

suspicion). These jurisdictions reason that no communication is

required because the officers are working together on the same

investigation; the officers thus have a "nexus to the

investigation," Goff, supra, are "involved in the [same]

investigation," United States v. Fiasconaro, 315 F.3d 28, 36

(1st Cir. 2002), or are acting as a "single organism," Shareef,

100 F.3d at 1504 n.6.

ii. Horizontal collective knowledge doctrine under

art. 14. The defendant urges us to reject all forms of the

horizontal collective knowledge doctrine; he argues that the

doctrine of horizontal collective knowledge undermines the

deterrent effect of the exclusionary rule and is offensive to

the requirements of art. 14. The Commonwealth argues that we

need not reach the issue here, because Doherty had reasonable

suspicion without imputing the knowledge of Dwan and Lopez to

him.
 22

We conclude that, to comport with art. 14, application of

the horizontal collective knowledge doctrine must be limited,

but not so much so that it disregards the practical reality of

effective law enforcement. See Beck v. Ohio, 379 U.S. 89, 91

(1964) ("The rule of probable cause is a practical, nontechnical

conception affording the best compromise that has been found for

accommodating . . . often opposing interests. Requiring more

would unduly hamper law enforcement. To allow less would be to

leave law-abiding citizens at the mercy of the officers' whim or

caprice" [citation omitted]).

Where there is no directive or instruction from a superior

officer, in order to aggregate officers' knowledge for use in

the determination of reasonable suspicion without running afoul

of art. 14, the officers must be involved in a joint

investigation, with a mutual purpose and objective, and must be

in close and continuous communication with each other about that

objective. See, e.g., United States v. Sandoval-Venegas, 292

F.3d 1101, 1105 (9th Cir. 2002). While the acting officer need

not have knowledge of all of the facts giving rise to reasonable

suspicion or probable cause, the officer must have knowledge of

at least some of the critical facts. See, e.g., United States

v. Bernard, 623 F.2d 551, 560-561 (9th Cir. 1979).

In order for their knowledge to be pooled such that "[i]n

effect all of them participated in the decision to make the
 23

arrests," Bernard, 623 F.2d at 560, the officers must be

actively involved in the same investigation, with a shared and

mutual objective. See United States v. Nafzger, 974 F.2d 906,

914 (7th Cir. 1992) (all officers "were part of a coordinated

investigation" of defendant who was suspected of being involved

in organized crime ring). The officers must be "functioning as

a team," as opposed to working as "independent actors who merely

happen to be investigating the same subject" (citation omitted).

See Ramirez, 473 F.3d at 1033; Gillette, 245 F.3d at 1034.

"'Working as a team' is also conceptualized as agents

working 'in close communication with one another.'" United

States v. Duval, 742 F.3d 246, 253 (6th Cir.), cert. denied, 574

U.S. 823 (2014), quoting Woods, 544 F.2d at 260. See, e.g.,

Sandoval-Venegas, 292 F.3d at 1105-1106 (detectives

investigating bank robbery "were in continuous collective

contact" during pursuit of robber, and one of detectives at

scene of arrest knew of facts establishing probable cause and

was standing at elbow of officer who made arrest, such that

arresting officer need not be viewed as "an island," but,

rather, "their pooled knowledge" could be considered to support

probable cause for apprehension of suspected robber). "The

inquiry in such a circumstance is 'whether the individual

officers have communicated the information they possess

individually, thereby pooling their collective knowledge' to
 24

satisfy the relevant standard." United States v. Whitley, 680

F.3d 1227, 1234 n.3 (10th Cir. 2012), quoting Chavez, 534 F.3d

at 1345.

For officers in a joint investigation to be considered in

close communication, they must be continuously conferring with

each other throughout the course of the investigation,

exchanging information to the extent possible. See State v.

Barnes, 58 Haw. 333, 336 (1977), and cases cited ("While police

officers are acting in concert and are keeping each other

informed of the progress of a particular investigation, the

knowledge of each is deemed to be the knowledge of all").

"Basing the legitimacy of the stop solely on what the

officer who first approaches the suspect knows" rather than on

the collective knowledge of the officers involved and

communicating throughout the stop "makes little sense from a

practical standpoint." See United States v. Cook, 277 F.3d 82,

86 (1st Cir. 2002). At the same time, the doctrine of

horizontal collective knowledge "does not allow officers to make

arrests without probable cause simply because some other

officer, somewhere, has probable cause to arrest." See Ochoa,

131 Ariz. at 177. Although all the information giving rise to

reasonable suspicion or probable cause need not be explicitly

communicated to the acting officer, some of the "critical

information" supporting the constitutional justification must be
 25

shared with, or otherwise known to, that officer, and the

exchange of information among the group of officers must be such

that "the knowledge of one of them [is] the knowledge of all"

(citation omitted). Bernard, 623 F.2d at 561.

This approach duly balances the right of individuals to be

free from unreasonable searches and seizures with the practical

needs of officers jointly conducting investigations that are

unfolding from moment to moment. See Commonwealth v. Feliz, 486

Mass. 510, 515 (2020), quoting Commonwealth v. Catanzaro, 441

Mass. 46, 56 (2004) ("There is no ready test for reasonableness

except by balancing the need to search or seize against the

invasion that the search or seizure entails"). See also Cook,

277 F.3d at 86 ("common sense and practical considerations must

guide judgments about the reasonableness of searches and

seizures"). It provides flexibility in "dynamic environment[s]

marked by the potential for violence," where officers may have

no opportunity to communicate each piece of relevant information

during the course of the stop, see id., while nonetheless

necessitating general communication amongst officers in order

for a stop to pass constitutional muster.

The approach suggested by Justice Cypher, by contrast,

would allow post hoc rationalizations by scouring all of the

information any number of officers had gathered on a particular

subject, over an unlimited time frame and in any location, to
 26

cobble together a justification for the stop. Indeed, in her

view, the officer making the stop would not have to have

knowledge of any of the facts establishing reasonable suspicion

to conduct the stop, nor would any other individual officer.

The approach suggested by Justice Wendlandt, on the other

hand, would require officers who have been in hot pursuit of a

fleeing suspect, communicating over police radio broadcasts, to

stop and confer with each other about the facts known to each of

them before deciding whether they had sufficient information to

stop the suspect, who would be unlikely to stand and wait for

this conference to end before continuing to flee. We discern no

reason why police using electronic communication while in

pursuit should be held to this heightened standard. See

Hensley, 469 U.S. at 231, quoting United States v. Robinson, 536

F.2d 1298, 1300 (9th Cir. 1976) ("effective law enforcement

cannot be conducted unless police officers can act on directions

and information transmitted by one officer to another and . . .

officers, who must often act swiftly, cannot be expected to

cross-examine their fellow officers about the foundation for the

transmitted information"). Where each officer has communicated

his or her knowledge to the others during the course of the

pursuit, this shared knowledge is sufficient to establish

reasonable suspicion, and the officer conducting the stop is
 27

aware of some of the critical elements, the requirements of

art. 14 are satisfied.

Contrary to Justice Wendlandt's assertions, our approach

would not permit an officer on patrol to stop an individual at

random and then attempt to create a post hoc justification based

on other officers' knowledge from some previous investigation.

The officers all must be involved in a joint, ongoing

investigation, and in close communication as they pursue the

suspect. Although Justice Wendlandt views the stop here as

"rest[ing] on the hope that, post hoc, a judge will cobble

together information known to other officers on the team" about

which the acting officer is "entirely ignorant and has no basis

to believe is known to a fellow officer," post at , in

actuality, the officer who had heard the information about the

suspect having a beard was standing at the elbow of the officer

who initiated the stop, just as Justice Wendlandt states would

be acceptable under the inevitable discovery exception to the

exclusionary rule. See post at . Use of the inevitable

discovery exception would not, however, address all

circumstances that officers might encounter in the course of a

developing, real-time pursuit. Here, for instance, had Dwan

turned onto another road perpendicular to Morrissey Boulevard

and within blocks of the scene of the crime, he would have been

heading in a completely different direction from the location of
 28

the stop, and yet still in the reported path of flight; and he

might not have encountered the defendant before he was able to

reach nearby commercial areas from which the defendant might

have been able to perfect an escape.

The approach we adopt balances the right of the suspect to

be free from unreasonable searches, with the need of law

enforcement and the public to stop someone who is fleeing the

scene after having committed a violent crime before further

violence is visited upon the public. See Terry, 392 U.S. at 27.

As Justice Wendlandt asserts, post at , quoting Terry, supra

at 10, Terry's "strictly circumscribed permission was designed

to give the officer on the scene 'an escalating set of flexible

responses, graduated in relation to the amount of information'

possessed by the officer, during the 'rapidly unfolding and

often dangerous situations' the officer faces, especially in the

nation's cities." Her approach, however, distorts this balance.

Accordingly, here, we conclude that Dwan's knowledge may be

considered in the calculus of reasonable suspicion pursuant to

the horizontal collective knowledge doctrine, but we decline to

impute Lopez's knowledge to Doherty. The defendant maintains

that Lopez's knowledge may not be imputed to Doherty because

there is no evidence that Lopez communicated the results of his

search. We agree with the defendant that Lopez's knowledge may

not be imputed, but for a different reason: there is no
 29

evidence in the record indicating that Lopez communicated at all

with Doherty or over channel six prior to the stop of the

defendant. Thus, despite being involved in a joint effort, the

continuous communication requirement was not met, and Lopez's

knowledge of the absence of people in the area of Victory Road

therefore cannot be imputed to Doherty. See Commonwealth v.

Hawkins, 361 Mass. 384, 386-387 & n.3 (1972) (declining to

impute knowledge about stolen bonds to officers who seized

bonds, absent probable cause, where there was no evidence of

communication or cooperative effort). See, e.g., United States

v. Villasenor, 608 F.3d 467, 476-477 (9th Cir.), cert. denied,

562 U.S. 1020 (2010) (declining to aggregate knowledge of

immigration and customs enforcement agents and inspectors of

customs and border protection where "[t]he record [was] devoid

of any communication" amongst agents).

The defendant also argues that the motion judge did not

find the predicate facts that would permit any application of

the horizontal collective knowledge doctrine here.

Specifically, the defendant maintains that, by omitting mention

of the beard from her analysis of reasonable suspicion, the

judge actually made a contrary finding that neither Doherty nor

Dwan had had knowledge of the subsequent dispatches that

reported that the suspect had facial hair. The defendant

contends that the judge's omission itself was a finding.
 30

We do not read the judge's findings so narrowly. The only

finding the judge made with respect to the description of facial

hair was in a footnote, in which the judge noted that "[t]here

was no mention in the original broadcast about facial hair

(emphasis added)." Thus, it is unclear whether the judge found

that Doherty heard the subsequent two broadcasts. Even if we

were to assume that this footnote was a finding that Doherty did

not hear the subsequent broadcasts detailing the additional

descriptions that mentioned facial hair, the record makes clear

that Dwan did hear them, and thus, we impute his knowledge to

Doherty.

"[A]n appellate court may supplement a motion judge's

subsidiary findings with evidence from the record that 'is

uncontroverted and undisputed and where the judge explicitly or

implicitly credited the witness's testimony.'" Jones-Pannell,

472 Mass. at 431, quoting Commonwealth v. Isaiah I., 448 Mass.

334, 337 (2007). Any supplemental facts taken from the record

"may not contradict the motion judge's findings." Commonwealth

v. Garner, 490 Mass. 90, 94 (2022), citing Isaiah I., supra.

Nor does "a general statement crediting witness testimony mean[]

that every statement the witness makes on the stand is

automatically a fact found by the motion judge." Garner, supra.

Here, the audio recordings from the dispatch, which were

introduced at the hearing, as well as Dwan's testimony, confirm
 31

that Dwan was actively engaged in communications with the

dispatcher who relayed the later descriptions. None of this

information is contrary to any of the judge's findings or

ultimate conclusions of law, and the judge did not reject any

part of Dwan's testimony as not credible. Accordingly, we can

conclude, consistent with the judge's findings, that Dwan was

aware that the suspect had been described as having facial hair.

See Jones-Pannell, 472 Mass. at 431.

Given this, Dwan's knowledge may be imputed to Doherty

through the horizontal collective knowledge doctrine. Dwan and

Doherty were actively working on apprehending the suspect

involved in the armed robbery; indeed, they arrived at the scene

of the stop contemporaneously. The two officers jointly

conducted a patfrisk of the defendant's person and backpack.

This is more than sufficient to be considered a joint

investigation for a shared, mutual objective. See Sandoval-

Venegas, 292 F.3d at 1104 (upholding arrest that was "the

culmination of the efforts of two detectives who were working

together, in close communication and consultation, and who were

both present at the arrest"). Additionally, Dwan continuously

provided updates over channel six about the status of his

investigation, which Doherty testified to having monitored.

That Dwan was in continued, close communication with channel

six, and with Doherty upon arrival, further supports application
 32

of the horizontal knowledge doctrine. See id. This was not a

case where Dwan and Doherty were working in isolation and

"merely happen[ed] to be investigating the same subject." See

Gillette, 245 F.3d at 1034. Accordingly, Dwan's information

that the suspect had a beard, and that no one else was outside

on Morrissey Boulevard or Victory Road, may be imputed to

Doherty.

iii. Over-all calculus of reasonable suspicion. The

defendant argues that, even taking account of all the

circumstances, Doherty lacked reasonable suspicion at the time

of the investigatory stop, and his motion to suppress should

have been allowed. We do not agree.

The similarity of the physical description of the suspect

to the defendant, the temporal and physical proximity of the

defendant to the scene of the robbery, and the context of the

stop gave rise to reasonable suspicion, with or without the

information that the suspect had facial hair. See Commonwealth

v. Henley, 488 Mass. 95, 103 (2021) ("Although, standing alone,

any one of these factors might not have been sufficient to

justify the stop, when viewed as a whole, . . . they gave rise

to reasonable suspicion").

We have cautioned that a match between a defendant's

appearance and a general description alone does not amount to

reasonable suspicion, particularly if that general description
 33

could fit a large number of people in the area where the stop

occurred. See Commonwealth v. Warren, 475 Mass. 530, 535 (2016)

(description of three Black males wearing dark clothing, with

one wearing red hoodie, absent description of any facial

features, hairstyles, height, weight, or other physical

characteristics, was insufficient to establish reasonable

suspicion); Commonwealth v. Cheek, 413 Mass. 492, 496 (1992)

("the description of the suspect as a '[B]lack male with a black

[three-quarter] length goose' could have fit a large number of

men who reside in the Grove Hall section of Roxbury").

At the time of the stop here, however, Doherty knew that

the suspect had been described as a Black male, twenty-eight or

twenty-nine years old, with a medium build, and five feet, seven

inches to five feet eight inches tall. He also knew that the

suspect had been described as having facial hair, wearing blue

jeans7 and a blue hoodie, and carrying a silver firearm. The

defendant generally matched the description of the suspect, in

terms of age, height, skin tone, build, and facial hair. Thus,

the correspondence between the defendant's appearance and the

7 The judge found that the dispatched description of the
suspect was for a male with dark jeans. The 911 call placed by
the victim, however, as well as the radio transmission and
Doherty's testimony at the hearing "make clear that the report
said that the jeans were blue." Privette, 100 Mass. App. Ct. at
223 n.3.
 34

description of the suspect was not so generalized as to preclude

giving rise to reasonable suspicion.

Undoubtedly, the defendant's appearance did not match the

description of the suspect in every particular. The defendant

was wearing a green sweater, black jeans,8 and a red plaid

backpack. In context, the absence of the red backpack in the

broadcast description is of little significance. Backpacks,

like sunglasses, hats, or a mask, are easily worn, taken off,

changed, or discarded. See Commonwealth v. Staley, 98 Mass.

App. Ct. 189, 192 (2020).

In addition, as stated, the physical similarities between

the defendant's appearance and the description of the suspect

were supplemented by the defendant's geographic proximity to the

location of the robbery within minutes of it having taken place.

The defendant appears to suggest that his proximity to the scene

weighs against a finding of reasonable suspicion, because had he

been the robber, he would have traveled farther from the scene

in the seven minutes that had elapsed since the robbery. See

Warren, 475 Mass. at 536-537 (stop of defendant one mile from

scene, twenty-five minutes later, where there was no reported

8 Doherty initially testified that the defendant was wearing
blue jeans, but, on cross-examination, after having had his
recollection refreshed by the booking sheet, Doherty testified
that the defendant's jeans were black. Both the Commonwealth
and the defendant agree that the jeans he wore at the time of
the stop were black.
 35

flight path, had little weight in calculus of reasonable

suspicion). We are not convinced.

Here, there was a reported path of flight, and the

defendant was found seven minutes after the initial dispatch on

a street directly behind the gasoline station that had been

robbed. The defendant's location was consistent with the

reported flight path, which was in the direction of the pharmacy

on Morrissey Boulevard. Both the timing and the location of the

stop in relation to the armed robbery thus weigh in favor of a

finding of reasonable suspicion. See Warren, 475 Mass. at 536

("Proximity is accorded greater probative value in the

reasonable suspicion calculus when the distance is short and the

timing is close"). Indeed, given the other circumstances

present here, the physical description of the defendant's

height, build, age, skin tone, clothing, and firearm was

sufficient to establish reasonable suspicion even without any

mention that the suspect had facial hair.

The defendant argues that being the only person in the area

at that hour of the morning is not dispositive. We agree that,

taken alone, his location at the time of the stop would be

insufficient to warrant a finding of reasonable suspicion. But,

given that he was the only person in the vicinity of the robbery

at 3:43 A.M., in the rain, within seven minutes of the reported
 36

robbery, the articulable facts combine to establish reasonable

suspicion that the defendant had committed the armed robbery.

Order denying motion to
suppress affirmed.
 CYPHER, J. (concurring in part and dissenting in part). I

agree with the court that Officer Brian Doherty had sufficient

reasonable suspicion to stop the defendant as a suspect in the

armed robbery.1 I disagree, however, that the court should

1 I agree with the court and with Justice Wendlandt that
reasonable suspicion in this case is not dependent on the
collective knowledge doctrine (therefore, I would have declined
to reach the application of the doctrine to this case and
beyond). At around 3:36 A.M., Doherty received a radio
transmission indicating that there was an armed robbery of a
gasoline station on Morrissey Boulevard in the Dorchester
section of Boston, describing the suspect as "a Black male, late
twenties, medium build, five foot seven, blue hoodie, blue
jeans, on foot toward[]" a pharmacy. Doherty was listening to
the police department radio channel as he headed to the area and
heard Lieutenant (then Sergeant) Daryl Dwan report that he did
not see anyone on Morrissey Boulevard. Canvassing the nearby
Clam Point neighborhood, he drove through about nine additional
streets without seeing a single person. Approximately seven
minutes after the dispatch, Doherty saw the defendant on a
street close to the gasoline station and easily accessible by an
opening in a fence or by walking along several streets. The
defendant is a Black male, five feet, eleven inches tall, 220
pounds, and was thirty-two years old at the time, wearing a dark
sweater and jeans, and was the only person on the street at
approximately 3:30 A.M. Even without considering the
defendant's beard, there was reasonable suspicion to stop him.
Commonwealth v. Evelyn, 485 Mass. 691, 704-705 (2020) (defendant
one-half mile away from location of crime thirteen minutes after
it occurred supported reasonable suspicion). Contrast
Commonwealth v. Warren, 475 Mass. 530, 535-536 (2016) (no
reasonable suspicion where description was vague and did not
include "any information about facial features, hairstyles, skin
tone, height, weight, or other physical characteristics," but
recognizing "[p]roximity is accorded greater probative value
. . . when the distance is short and the timing is close").

Nonetheless, considering the record, it is very likely that
Doherty heard the dispatch including the description of facial
hair. The description of the suspect having facial hair was
broadcast on the department channel at around 3:38 A.M., two
 2

dismantle the collective knowledge doctrine as it has been

discussed and appropriately applied in cases in this

Commonwealth for more than fifty years. I would uphold the

collective knowledge doctrine in situations where officers are

engaged in a cooperative effort. I would not dissect whether

officers are in sufficiently "close and continuous communication

with each other" about their "shared objective," nor would I

examine whether the acting officer is aware "of at least some of

the critical facts" in determining whether to aggregate their

knowledge. Ante at . I respectfully dissent.

I begin my analysis by considering the theoretical

framework in which search and seizure analysis typically has

been conducted, whether under the Fourth Amendment to the United

States Constitution or art. 14 of our Declaration of Rights.

Although the discussion of the utility of the collective

knowledge doctrine concerns each officer's subjective knowledge

minutes after the first description, and at least three minutes
before Doherty stopped the defendant. Although Doherty agreed
with defense counsel on cross-examination that the first
description was the only transmittal he heard before he stopped
the defendant, he testified on direct examination, without
prompting, that the call was for a man "with a beard," and
affirmed that description on cross-examination. The motion
judge made no finding addressing Doherty's knowledge of facial
hair. Commonwealth v. Jones-Pannell, 472 Mass. 429, 431 (2015)
(appellate court may supplement motion judge's findings of fact
with uncontroverted record evidence where judge explicitly
credited witness's testimony and where facts do not detract from
judge's ultimate findings).
 3

when working together with others, the reasons we do not

consider the intent or motive of individual officers apply

equally to knowledge and are instructive. See, e.g.,

Commonwealth v. Long, 485 Mass. 711, 724 n.9 (2020) (in

determining whether traffic stop was racially discriminatory,

judge may consider whether officer observed or followed vehicle

for extended period of time or whether officer would have been

able to note defendant's race).

"Fourth Amendment doctrine, given force and effect by the

exclusionary rule," is intended primarily to regulate the day-

to-day activities of police officers and should be expressed in

readily applicable terms for implementation by law enforcement.

Clancy, The Purpose of the Fourth Amendment and Crafting Rules

to Implement That Purpose, 48 U. Rich. L. Rev. 479, 505 (Jan.

2014), quoting New York v. Belton, 453 U.S. 454, 458 (1981).

"A highly sophisticated set of rules, qualified by all
sorts of ifs, ands, and buts and requiring the drawing of
subtle nuances and hairline distinctions, may be the sort
of heady stuff upon which the facile minds of lawyers and
judges eagerly feed, but they may be literally impossible
of application by the officer in the field."

Clancy, supra, quoting Belton, supra.

Keeping that purpose in mind, "one of the main principles

of Fourth Amendment analysis for many years has been the

measurement of a police officer's intent by examining the

objective aspects of the encounter, as opposed to inquiry into
 4

the officer's actual, subjective intent." T.K. Clancy, The

Fourth Amendment § 11.6.2.1, at 767 (3d ed. 2017). See Brigham

City v. Stuart, 547 U.S. 398, 404 (2006), quoting Scott v.

United States, 436 U.S. 128, 138 (1978) ("An action is

'reasonable' under the Fourth Amendment, regardless of the

individual officer's state of mind, 'as long as the

circumstances, viewed objectively, justify [the] action'"

[emphasis added]); Indianapolis v. Edmond, 531 U.S. 32, 45

(2000) ("individual officer's subjective intentions are

irrelevant to the Fourth Amendment validity of a traffic stop

that is justified objectively by probable cause to believe a

traffic violation has occurred"); Bond v. United States, 529

U.S. 334, 338 n.2 (2000) ("The parties properly agree that the

subjective intent of the law enforcement officer is irrelevant

in determining whether that officer's actions violate the Fourth

Amendment"); Whren v. United States, 517 U.S. 806, 812-813

(1996) (decisions released by Court "foreclose any argument that

the constitutional reasonableness of traffic stops depends on

the actual motivations of the individual officers involved");

Newton, The Real-World Fourth Amendment, 43 Hastings Const. L.Q.

759, 770-771 (2016) ("As a general matter, courts assess whether

the Fourth Amendment was violated in a particular case by

applying an 'objective' standard. . . . [T]he 'subjective'

mental states of both the police officers and the persons they
 5

interacted with are generally irrelevant to the Fourth Amendment

analysis"); Tomkovicz, Rehnquist's Fourth: A Portrait of the

Justice as a Law and Order Man, 82 Miss. L.J. 359, 404-405

(2013), quoting Graham v. Connor, 490 U.S. 386, 396-397 (1989)

(discussing Justice Rehnquist's approach to Fourth Amendment,

"[e]valuations of reasonableness called for 'objective'

inquiries that pay 'careful attention to the facts and

circumstances of each particular case'"). But see Dix,

Subjective "Intent" as a Component of Fourth Amendment

Reasonableness, 76 Miss. L.J. 373 (2006) (critical analysis of

objective standard); Kinports, Criminal Procedure in

Perspective, 98 J. Crim. L. & Criminology 71 (2007) (arguing

Court shifts from objective to subjective tests); Raigrodski,

Reasonableness and Objectivity: A Feminist Discourse of the

Fourth Amendment, 17 Tex. J. Women & L. 153 (2008) (discussing

partiality in "objective" determinations of reasonableness);

Kerr, The Questionable Objectivity of Fourth Amendment Law, 99

Tex. L. Rev. 447 (Feb. 2021) (challenging true objectivity in

Fourth Amendment doctrine as applied by Court). "[A]lthough the

framing-era sources did not always agree on the details of the

criteria for regulating searches and seizures, they were united

in seeking objective criteria to measure the propriety of

governmental actions." Clancy, The Framers' Intent: John
 6

Adams, His Era, and the Fourth Amendment, 86 Ind. L.J. 979, 980

(2011).

"Reasonableness and the balancing of interests under the

Fourth Amendment is an objective inquiry." 1 J.W. Hall, Search

and Seizure § 2.14 (5th ed. Supp. Oct. 2013). This inquiry is

fact bound, and "is measured in objective terms by examining the

totality of the circumstances." Id., quoting Ohio v. Robinette,

519 U.S. 33, 39 (1996). "[T]he calculus of reasonableness must

embody allowance for the fact that police officers are often

forced to make split-second judgments -- in circumstances that

are tense, uncertain, and rapidly evolving." Kentucky v. King,

563 U.S. 452, 466 (2011), quoting Graham, 490 U.S. at 396-397.

The subjective intent of the officers is generally irrelevant;

"the only real questions are what do the objective facts show

and is this objectively reasonable?" Hall, supra. See 68 Am.

Jur. 2d Searches and Seizures § 13 (2020) ("An action is

reasonable under the Fourth Amendment regardless of the

individual officer's state of mind as long as the circumstances,

viewed objectively, justify the action; the officer's subjective

motivation is irrelevant"). Even where an officer declared at

the hearing on a motion to suppress that the officer did not

believe he or she had sufficient facts to amount to probable

cause, that personal opinion is not fatal to the Commonwealth's
 7

case. 2 W.R. LaFave, Search and Seizure § 3.2(b), at 46 (6th

ed. 2020).

"[T]he mere subjective conclusions of a police officer
concerning the existence of probable cause is not binding
on this court which must independently scrutinize the
objective facts to determine the existence of probable
cause. . . . Moreover, since the courts have never
hesitated to overrule an officer's determination of
probable cause when none exists, consistency suggests that
a court may also find probable cause in spite of an
officer's judgment that none exists."

LaFave, supra, quoting United States ex rel. Senk v. Brierley,

381 F. Supp. 447, 463 (M.D. Pa. 1974). See Re, Fourth Amendment

Fairness, 116 Mich. L. Rev. 1409, 1460 (June 2018) ("[P]olice

can act reasonably without being motivated by the considerations

that make their conduct reasonable. . . . [Where there are

reasonable grounds to act,] requiring that the officer correctly

glean the proper basis for her actions would not afford innocent

persons any greater protection, and insistence on police

perfection would create windfalls for wrongdoers. This default

indifference to police motivation aligns with the case law,

which focuses on objectively available reasons for action").

Correspondingly, in Massachusetts, "[s]ubjective intentions

play no role" in the reasonable suspicion analysis. J.A.

Grasso, Jr., & C.M. McEvoy, Suppression Matters Under

Massachusetts Law § 4-3[b] (2022 ed.). See Commonwealth v.

Buckley, 478 Mass. 861, 865-866 (2018) ("under the authorization

test, a stop is reasonable under art. 14 as long as there is a
 8

legal justification for it"); Commonwealth v. Cruz, 459 Mass.

459, 462 n.7 (2011) ("The subjective intentions of police are

irrelevant so long as their actions were objectively

reasonable"). "Evaluating the validity of police conduct on the

basis of objective facts and circumstances, without

consideration of the subjective motivations underlying that

conduct, is justified in part based on the significant

evidentiary difficulties such an inquiry into police motives

would often entail." Buckley, supra at 867. Only recently have

we made an exception to the objective standard in search and

seizure cases in which a defendant alleged race as the reason

for a traffic stop based on a pretext; this exception is founded

not on art. 14 or the Fourth Amendment, but on our equal

protection jurisprudence set out in arts. 1 and 10 of the

Declaration of Rights and the Fourteenth Amendment to the United

States Constitution. Long, 485 Mass. at 715, 729.2 The analysis

2 See Long, 485 Mass. at 713 (establishing revised test for
defendants seeking to suppress evidence obtained as result of
racially motivated traffic stop); Commonwealth v. Lora, 451
Mass. 425, 426 (2008) (exclusionary rule applies to evidence
from traffic stop violative of equal protection where stop was
product of selective enforcement based on race). In inventory
and special needs searches and administrative inspections, the
Supreme Court has looked to subjective intent in analyzing the
validity of government action. See Brigham City, 547 U.S. at
405, quoting Edmond, 531 U.S. at 46 ("we have held in the
context of programmatic searches conducted without
individualized suspicion -- such as checkpoints to combat drunk
driving or drug trafficking -- that 'an inquiry into a
 9

in such cases occasionally refers to an officer's intent,

motivation, or state of mind; and in some instances, the

officer's knowledge. See id. at 724-725 (listing factors judges

should consider in applying totality of circumstances test to

determine whether traffic stop was violative of equal

protection); Commonwealth v. White, 469 Mass. 96, 101-102 (2014)

(officer's examination of pills transformed search from

inventory into investigatory); Commonwealth v. Judge, 95 Mass.

App. Ct. 103, 108 (2019) (administrative and special needs

searches may not become pretext for investigative search). See

also Newton, The Real-World Fourth Amendment, supra at 771

("There are some rare exceptions to the general 'objective'

nature of legal analysis under the Fourth Amendment," such as

police roadblocks).

programmatic purpose' is sometimes appropriate"); Whren, 517
U.S. at 812 ("we [have] never held, outside the context of
inventory search or administrative inspection . . . that an
officer's motive invalidates objectively justifiable behavior
under the Fourth Amendment"); Florida v. Wells, 495 U.S. 1, 4
(1990) (inventory search may not be "ruse for a general
rummaging in order to discover incriminating evidence"). See
also Commonwealth v. Judge, 95 Mass. App. Ct. 103, 108 (2019),
quoting Commonwealth v. Carkhuff, 441 Mass. 122, 126 (2004)
("Administrative and special needs searches 'must be conducted
as part of a scheme that has as its purpose something "other
than the gathering of evidence for criminal prosecutions"'").
But see Commonwealth v. Feliz, 481 Mass. 689, 700 n.17 (2019),
S.C., 486 Mass. 510 (2020) ("We have yet to justify searches of
individuals on the basis of the special needs exception").
 10

In other words, we always have examined the totality of the

circumstances to determine whether a search or seizure was

reasonable. The reason for conducting an objective analysis

includes the recognition that the Fourth Amendment, and art. 14,

regulate conduct rather than thoughts. See Ashcroft v. al-Kidd,

563 U.S. 731, 736 (2011). "[I]njecting subjectivity into Fourth

Amendment reasonableness would require officers to 'act on

necessary spurs of the moment with all the knowledge and acuity

of constitutional lawyers'" (citation omitted). Barmore,

Authoritarian Pretext and the Fourth Amendment, 51 Harv. C.R.-

C.L. L. Rev. 273, 297 (2016).

Additionally, analyzing the intent behind an officer's

actions "could cause unacceptable variation in the Fourth

Amendment's application" where its focus on objectivity is meant

to promote "evenhanded, uniform enforcement of the law."

Barmore, supra at 298, quoting Ashcroft, 563 U.S. at 736. As a

practical matter, determining the nature of subjective motives

underlying an individual officer's action is difficult. See

Brigham City, 547 U.S. at 405 ("It . . . does not matter here --

even if their subjective motives could be so neatly unraveled --

whether the officers entered the kitchen to arrest respondents

and gather evidence against them or to assist the injured and

prevent further violence"); Harlow v. Fitzgerald, 457 U.S. 800,

816-817 (1982) (in discussing qualified immunity, "[j]udicial
 11

inquiry into subjective motivation therefore may entail broad-

ranging discovery and deposing of numerous persons, including an

official's professional colleagues," which may be "peculiarly

disruptive of effective government").

For the same reasons, when several officers are working

together, it will be difficult to decipher the precise knowledge

that each individual officer had at various points in the

investigation, whether the acting officer had knowledge of "some

of the critical facts," and whether the communications between

the officers were sufficiently close and continuous and touched

on the "objective" of the police with respect to the

investigation. Ante at . Taking into consideration the

knowledge of all the officers involved in a police action is

consistent with an objective analysis of the totality of the

circumstances. See Coleman, Beyond the Four Corners: Objective

Good Faith Analysis or Subjective Erosion of Fourth Amendment

Protections?, 54 Mercer L. Rev. 1719, 1724 (2003) ("the

objective standard is framed by the officer's knowledge and

understanding of the requirements of the Fourth Amendment. . . .

Objective good faith, then, rests on a foundation of Fourth

Amendment compliance, not individualized, subjective knowledge

of facts known only to the officer"); LaFave, supra at § 9.5(a),

at 660-661 ("Certainly it is clear beyond question that the

'reasonable belief' required for arrest is not to be determined
 12

by what the arresting officer did or did not believe, but rather

by whether the available facts would 'warrant [an officer] of

reasonable caution in the belief' that the person arrested had

committed an offense. . . . [The reasonable suspicion] test, as

is the case with the legal standard for arrest, is purely

objective and thus there is no requirement that an actual

suspicion by the officer be shown" [citation omitted]); R.G.

Stearns, Massachusetts Criminal Law: A Prosecutor's Guide,

Threshold Inquiries (42d ed. 2023), quoting Commonwealth v.

Stoute, 422 Mass. 782, 790 (1996) ("facts must be assessed in

light of the collective knowledge of the officers involved" and

"[t]he test is an objective one, 'view[ing] the circumstances as

a whole'"). Application of the court's new rule shifts the

Fourth Amendment and art. 14 focus from the objective conduct of

the police to the subjective thought process of the first

officer to reach the suspect, and too closely examines the

precise frequency and content of communications between officers

cooperating in an investigation. I would keep the existing

doctrine in place, in which a judge need not consider the inner

workings of the minds of each individual officer at the relevant

time, but the collective knowledge of all officers working

together at the time of a stop, search, or arrest. Although I

think that communication between officers is a good indicator

that they are acting as a team, to inquire into the sufficiency
 13

of the communications between collaborating officers in order to

aggregate their knowledge will prove difficult for judges trying

to apply the new rule, and for officers striving to integrate

the court's holding into their daily practices.

In United States v. Cook, 277 F.3d 82, 86 (1st Cir. 2002),

the United States Court of Appeals for the First Circuit

discussed the reasoning supporting the aggregation of knowledge

among officers who are collaborating in a joint effort and held

that the knowledge of each officer should be imputed to all

officers jointly involved in an investigative stop. "As the

Supreme Court has repeatedly noted, common sense and practical

considerations must guide judgments about the reasonableness of

searches and seizures." Id. Imputing the knowledge of all the

officers working together is practical where "[i]nvestigative

stops generally occur in a dynamic environment marked by the

potential for violence"; it would make little sense to base the

legitimacy of the stop solely on the knowledge of the first

officer to reach the suspect. Id. This takes into account the

reality of many investigative stops conducted by multiple

officers: "rarely will [officers] have an opportunity to confer

during the course of the stop." Id.3

3 Several jurisdictions have upheld the horizontal
collective knowledge doctrine without requiring communication of
specific facts among officers so long as they are working
 14

together. See United States v. Whitfield, 634 F.3d 741, 746 (3d
Cir. 2010) ("It would make little sense to decline to apply the
collective knowledge doctrine in a fast-paced, dynamic situation
such as we have before us, in which the officers worked together
as a unified and tight-knit team; indeed, it would be
impractical to expect an officer in such a situation to
communicate to the other officers every fact that could be
pertinent in a subsequent reasonable suspicion analysis");
United States v. Nunez, 455 F.3d 1223, 1226 (11th Cir. 2006)
(reasonable suspicion determined from "collective knowledge of
the officers"); United States v. Ledford, 218 F.3d 684, 689 (7th
Cir. 2000) ("Because the search was a joint endeavor, the court
may properly consider what . . . the other officers knew [in
addition to the officer who opened the trunk during the
search]. . . . Were it otherwise, the validity of such jointly
conducted searches might turn on the fortuity of which officer
happened to open a trunk or door, notwithstanding the fact that
he and his colleagues were acting in concert"). But see United
States v. Ellis, 499 F.3d 686, 690 (7th Cir. 2007) (refusing to
impute knowledge of one officer to another to validate decision
to enter home because they were not in communication regarding
suspect); United States v. Roberts, 410 F. Supp. 3d 1268, 1282
(N.D. Fla. 2019), quoting United States v. Willis, 759 F.2d
1486, 1494 (11th Cir. 1985) ("collective knowledge doctrine
applies to cases in which the government agents maintained 'at
least a minimal level of communication during their
investigation'"). See also In re M.E.B., 638 A.2d 1123, 1129-
1133 (D.C. 1993), cert. denied, 513 U.S. 883 (1994) (aggregating
uncommunicated information between officers, holding that this
result "recognizes that when faced with a fast moving sequence
of events involving a number of police officers, a citizen's
rights are protected if, at the time of the intrusion, the
information collectively known to the police is constitutionally
sufficient to justify that intrusion"); State v. Goff, 129
S.W.3d 857, 863-864 (Mo. 2004) ("collective information in the
possession of those with a nexus to the investigation can be
considered in determining whether reasonable suspicion existed,"
rejecting defendant's "argument that each officer is required to
repeat his or her information to the officer making the stop in
order to make the stop a constitutional one"); State v.
Fioravanti, 46 N.J. 109, 122 (1965), cert. denied, 384 U.S. 919
(1966) ("Probable cause must be judged on the basis of
[officers'] composite information, and if that knowledge in its
totality shows probable cause, a police[ officer] who makes the
arrest upon an ensuing order to do so, acts upon probable
 15

This reasoning closely tracks the reasoning of the Supreme

Court in United States v. Hensley, 469 U.S. 221, 231-232 (1985),

in which it expanded on the collective knowledge doctrine by

allowing reliance on a flyer or bulletin issued by another

officer or police department to support a stop so long as the

flyer or bulletin was issued on the basis of articulable facts

supporting a reasonable suspicion. In making this

determination, the Court recognized that the rule is a matter of

"common sense," noting "effective law enforcement cannot be

conducted unless police officers can act on directions and

information transmitted by one officer to another and that

officers, who must often act swiftly, cannot be expected to

cross-examine their fellow officers about the foundation for the

transmitted information." Id. at 231, quoting United States v.

Robinson, 536 F.2d 1298, 1299 (9th Cir. 1976). Although in

Hensley, the Court was grappling with the vertical collective

knowledge doctrine, aggregating the knowledge of officers acting

cause"); People v. Gittens, 211 A.D.2d 242, 245-246 (N.Y. 1995)
(knowledge of officers "working in close temporal and spatial
proximity to one another" may be aggregated in reviewing
propriety of action taken); Woodward v. State, 668 S.W.2d 337,
344 (Tex. Crim. App. 1982), cert. denied, 469 U.S. 1181 (1985)
("when there has been some cooperation between law enforcement
agencies or between members of the same agency, the sum of the
information known to the cooperating agencies or officers at the
time of an arrest or search by any of the officers involved is
to be considered in determining whether there was sufficient
probable cause therefor").
 16

together also recognizes the need for officers to act "swiftly"

and efficiently. Hensley, supra.

In Massachusetts, as in other jurisdictions, when analyzing

probable cause, we look to the entire set of facts and

circumstances within the knowledge of the police. "[P]robable

cause exists where, at the moment of arrest, the facts and

circumstances within the knowledge of the police are enough to

warrant a prudent person in believing that the individual

arrested has committed or was committing an offense."

Commonwealth v. Santaliz, 413 Mass. 238, 241 (1992), quoting

Commonwealth v. Storey, 378 Mass. 312, 321 (1979), cert. denied,

446 U.S. 955 (1980). In discussing the collective knowledge

doctrine, the Appeals Court has referred to Santaliz and the

consideration of the "whole silent movie" as important to the

probable cause determination. Commonwealth v. Gant, 51 Mass.

App. Ct. 314, 318 (2001) (aggregating observations of two

separate officers to get to probable cause because "[b]oth

officers were engaged in a cooperative effort in the

investigation of this incident so that we may consider the

complete picture"); Commonwealth v. Garcia, 34 Mass. App. Ct.

386, 393 n.8 (1993) (noting collective knowledge doctrine and

probable cause standard). "A reviewing court may consider the

'whole silent movie,' [Santaliz, supra at 242,] disclosed to the

eyes of an experienced . . . investigator rather than
 17

'scrutinize in isolation' each of the facts and circumstances

known to the officers." Gant, supra, quoting Commonwealth v.

Kennedy, 426 Mass. 703, 708 (1998). See Hall, supra at § 6.10

("Probable cause is viewed objectively by reviewing courts and

is not based on the officer's subjective belief. If the rule

were otherwise, the citizenry would have significantly diluted

Fourth Amendment protection depending on whether the officer

chose to obtain a warrant before the arrest or search based on

subjective good faith. Only objective facts can be effectively

reviewed"). The court's approach requires a judge hearing

testimony in a motion to suppress, or a reviewing court, to

determine the extent of cooperation and communication for every

police move. Contrast Commonwealth v. Montoya, 464 Mass. 566,

576 (2013) (imputing knowledge of one officer to another,

"regardless of whether" it was communicated immediately by

radio).4

4 The facts of the present case underscore the difficulty in
determining precisely what was communicated to each officer at
which point during the investigation. Determining whether each
officer heard the communication regarding the beard before they
approached the defendant brings the court into murky waters.
Indeed, the motion judge avoided making any such finding.
Although the court does not entirely discard the horizontal
collective knowledge doctrine, the new rule still falls subject
to this difficulty. In order to apply the doctrine, a judge
will have to determine whether the acting officer had "critical
information" supporting the intrusion and discern whether that
officer was in continuous close communication with the other
officers (with knowledge) specifically with respect to their
 18

Similarly, when ascertaining whether reasonable suspicion

was sufficient, we have objectively examined the totality of the

specific, articulable facts presented. Commonwealth v. Meneus,

476 Mass. 231, 235 (2017). "The subjective intentions of police

are irrelevant so long as their actions were objectively

reasonable." Cruz, 459 Mass. at 462 n.7. It is of no matter

whether an officer is acting in "good faith." Commonwealth v.

Grandison, 433 Mass. 135, 139 (2001). See Commonwealth v.

Gentile, 466 Mass. 817, 822 (2014). "Reasonable suspicion is

measured by the 'totality of the circumstances' and from the

collective knowledge of the officers involved in the stop."

K. Wallentine, Street Legal: A Guide to Pre-trial Criminal

Procedure for Police, Prosecutors, and Defenders 7 (2d ed.

2020), quoting United States v. Sokolow, 490 U.S. 1, 2 (1989).

With these principles in mind, aggregating the knowledge of

officers working together in a cooperative effort in determining

whether probable cause or reasonable suspicion was sufficient at

the time of a stop or arrest conforms with our practice of

analyzing a situation objectively, without regard to the

subjective thought process of each separate officer involved.

To confine the reasonable suspicion or probable cause analysis

shared objective. Ante at . This requires the judge to
delve into the subjective thought process of not one, but
several different officers.
 19

to the facts known by the first officer to approach a suspect or

to those known by an officer with whom he was in continuous,

close communications with, when that officer is working

collaboratively with additional officers, would depreciate the

objectivity of the analysis.5

Contrary to the defendant's assertion that Massachusetts

dramatically has expanded and "strayed from its original

efficiency rationale," Massachusetts applied the collective

knowledge doctrine before the Supreme Court discussed the

doctrine in Whiteley v. Warden, Wyo. State Penitentiary, 401

U.S. 560, 568 (1971). See Stearns, supra, Searches Incident to

Arrest ("Massachusetts cases apply the collective knowledge

5 I agree with the court that the inevitable discovery
exception is not an adequate substitute for the horizontal
collective knowledge doctrine. Where evidence is discovered in
a manner that would compel its exclusion at a criminal trial
against the defendant, it may be admissible if the Commonwealth
can show by a preponderance of the evidence "that discovery of
the evidence by lawful means was certain as a practical matter,
'the officers did not act in bad faith to accelerate the
discovery of evidence, and the particular constitutional
violation is not so severe as to require suppression.'"
Commonwealth v. Hernandez, 473 Mass. 379, 386 (2015), quoting
Commonwealth v. Sbordone, 424 Mass. 802, 810 (1997). "This is a
'demanding test.'" Hernandez, supra, quoting Commonwealth v.
Balicki, 436 Mass. 1, 16 (2002). In a situation where several
officers are working as a team in pursuit of a suspect, and one
officer catches the suspect, it would be near impossible for the
Commonwealth to prove that his apprehension by another of the
officers was practically certain. See Hurlburt v. State, 425
P.3d 189, 194-195 (Alaska Ct. App. 2018) (discussing aggregation
of knowledge of collaborating officers based on "inevitable
discovery" rationale only applies to "unusual facts").
 20

doctrine in both the vertical and horizontal contexts, usually

without drawing a formal distinction between the two"). In

Commonwealth v. McDermott, 347 Mass. 246, 249-250 (1964), the

court discussed an arrest pursuant to a lawful warrant. The

warrant permitted the arrest of any individual at a particular

location "participating in any form of gaming," or any person

present if gaming materials were found. Id. at 247. The first

trooper on the scene saw the defendant registering bets. Id. at

249. When two police lieutenants arrived, the trooper told them

the defendant had "the stuff in his pockets." Id. at 248. As

the lieutenants questioned the defendant, the trooper observed

booking paraphernalia, notebooks, and personal belongings of the

defendant spread out on a counter. Id. The lieutenants, not

the trooper, subsequently arrested him. Id. The court held,

"It is without significance that [the trooper] was not [the] one

who made the arrest. The three officers were engaged in a

cooperative effort in the performance of their duty. The

knowledge of one was the knowledge of all." Id. at 249. See

Commonwealth v. Lanoue, 356 Mass. 337, 340 (1969) ("unnecessary

for the detaining officer to know all the information pertaining

to the incident" because knowledge of one is knowledge of all);

Commonwealth v. Ballou, 350 Mass. 751, 757 (1966), cert. denied,

385 U.S. 1031 (1967) ("elementary rule of composite knowledge of
 21

police officers engaged in a cooperative effort, where the

knowledge of one may be the knowledge of all").

The court also has recognized certain circumstances in

which the collective knowledge doctrine may not be applied. In

Commonwealth v. Hawkins, 361 Mass. 384, 385 (1972), officers

searched the defendant's apartment pursuant to a warrant

authorizing a search for drugs. The officers did not find any

drugs but did find an envelope containing United States savings

bonds with names and addresses that did not match that of the

defendant. Id. Another officer looked up the telephone number

of one of the persons whose name and address was indicated on

the bonds, and after a telephone conversation with the victim,

the defendant was arrested. Id. Before the officer made the

telephone call, the officers did not know that the bonds were

stolen. Previously, the victim had reported the stolen bonds at

a police station; none of the searching officers was aware of

that report. Id. at 385-386. The court held that the

collective knowledge doctrine could not be applied to aggregate

the knowledge of the officers because "the police were not aware

of the theft reported to station 9 nor were they engaged in a

cooperative effort with officers in connection with the stolen

bonds who did have this knowledge." Id. at 387.

Where officers are not engaged in a cooperative effort, the

court shall not apply the doctrine, thus limiting the danger of
 22

unconstitutional searches and seizures. Cf. Parsons v. United

States, 15 A.3d 276, 279, 281 (D.C. 2011) (trial court applied

collective knowledge doctrine improperly); Stearns, supra,

Searches Incident to Arrest ("While the 'fellow officer' rule

generally works to the advantage of police, it offers no

protection when the arresting officer acts at another officer's

deficient directions or stale or inaccurate information").

There is no need for the creation of the complex and perplexing

new rule that the court chooses to impose here.6 The court's

refusal in Hawkins to apply the collective knowledge doctrine

where officers were not engaged in a cooperative effort

6 It is worth noting that some of the cases relied on by the
court do not require such an extensive inquiry into the level of
communication between officers acting as a team, or the
sufficiency of the acting officer's knowledge of critical facts
on his or her own. See United States v. Ibarra, 493 F.3d 526,
530 (5th Cir. 2007) (requiring only "some degree of
communication" between arresting officer and officer who has
knowledge of all necessary facts); United States v. Gillette,
245 F.3d 1032, 1034 (8th Cir.), cert. denied, 534 U.S. 982
(2001) (requiring "some degree of communication" to ensure
officers functioning as "search team"); State v. Breeding, 200
So. 3d 1193, 1200 (Ala. Crim. App. 2015), quoting United States
v. Esle, 743 F.2d 1465, 1476 (11th Cir. 1984) (look to
collective knowledge of officers where group of officers
conducting operation and "there is at least minimal
communication among them"). In Gillette, where one officer
obtained consent to search vehicles, and another acting officer
responded to a call for backup and immediately started searching
the vehicles without knowledge of the consent, the court held
that "there was the requisite degree of communication" between
the officers to render the acting officer a member of the team,
and to uphold the search. Id. at 1033-1034.
 23

demonstrates that aggregating the knowledge of officers working

together complies with art. 14.

For over fifty years, Massachusetts courts consistently

have applied this doctrine in a horizontal manner where

appropriate. In Commonwealth v. Wooden, 13 Mass. App. Ct. 417,

418 (1982), three police officers -- Saunders, Williams, and

Callanan -- were patrolling when the defendant and another man

drew their attention. Saunders saw that the other man had

something in his hand that he was showing to the defendant. Id.

When the men noticed the unmarked cruiser in which the officers

were riding, they hurriedly moved down the street. Id.

Saunders saw the man drop a manila envelope. Id. Williams saw

the defendant had something clenched in his hand and appeared to

be putting something in his pocket. Id.

The officers got out of the car, and Saunders opened the

manila envelope, finding white powder in several wrapped

packages. Wooden, 13 Mass. App. Ct. at 418. Saunders placed

both the defendant and the other man under arrest. Id.

Searching the defendant after his arrest, Williams found packets

of cocaine and marijuana in the defendant's pockets. Id. at

418-419. The court recognized that Saunders personally did not

know that the defendant was clenching his hand and putting

something into his pockets. Id. at 421 ("[I]f Williams had been

acting alone, he could not have arrested either [party] without
 24

knowledge of the contents of the discarded envelope . . . . If

[Saunders] act[ed] alone, he could not have arrested the

defendant on the sole basis of the contents of the envelope

dropped by [the other man]"). Because "Saunders and Williams

were working in concert, and they were within an arm's reach of

each other as well as the suspects whom they were confronting,"

the court held that the knowledge of each officer could be

imputed to the other. Id. at 421-422, quoting W.R. LaFave,

Search and Seizure § 3.5 (c), at 633 (1978) ("They were 'in a

close time-space proximity to the questioned arrest [and]

search'").

In Commonwealth v. Rivet, 30 Mass. App. Ct. 973, 975

(1991), the Appeals Court rejected an argument made by the

defendant that knowledge of the officers should not be

aggregated because they did not communicate the known

information to one another. Officers Coyle and Dawes both

responded to a crash scene, and both determined that there was

probable cause to arrest the defendant for operating a motor

vehicle while under the influence of intoxicating liquor. Id.

at 974. Coyle arrived first and spoke with the defendant, who

told him that he had drunk one beer; during their conversation,

Coyle noticed that the defendant's eyes were glassy and arrested

him. Id. When Dawes arrived, approximately ten to fifteen

minutes before the defendant's arrest, he noticed that the
 25

defendant's eyes were bloodshot, there was a heavy odor of

alcohol coming from his breath, and he had difficulty speaking.

Id. Before Dawes arrived, he had spoken with witnesses who had

seen the defendant driving well over the speed limit just before

impact. Id. Although the Appeals Court concluded that the

information Coyle had on his own supported an inference of

intoxication, the knowledge of Coyle and Dawes could be

aggregated, recognizing that they "jointly participated in the

accident investigation." Id. at 975. "Probable cause to arrest

is determined upon an objective view of the facts." Id.

Applying the reasoning in Wooden, 13 Mass. App. Ct. at 421-422,

the court upheld the arrest. Rivet, supra.7

More recently, in Commonwealth v. Roland R., 448 Mass. 278,

285 (2007), the court applied the collective knowledge doctrine

to a set of facts highlighting its importance. The juvenile,

entering a court house, placed his bag through an X-ray machine

and walked through a metal detector. Id. at 280. When he was

7It is unclear whether the officers' knowledge in Rivet
would be aggregated to meet the probable cause standard under
the court's new rule. Were Coyle and Dawes in sufficiently
close communications about their objective? What precise
information was communicated from one officer to another?
Despite the fact that both Coyle and Dawes were on the scene
together for at least ten minutes, it is not evident whether
their knowledge could be aggregated any longer. See Rivet, 30
Mass. App. Ct. at 974. Not only is this illogical, but it is
inconsistent with our objective approach to search and seizure
questions.
 26

told by a court officer that his bag would be searched manually,

he stated that he did not want his bag searched and grabbed it,

turning to leave the building. Id. Officer Martinez, a police

officer assigned to the court house on that day, approached the

juvenile on the steps of the court house after being told what

had occurred. Id. The juvenile then ran from the court house,

as Martinez yelled for him to stop and broadcast his description

over the radio. Id.

Officer Conway, who was looking out a window on the second

floor of the court house, observed Martinez chasing the

juvenile. Roland R., 448 Mass. at 280. Conway joined in the

chase of the juvenile, along with five to ten other officers,

without knowing why the juvenile was being pursued. Id. After

several minutes of chasing the juvenile, Conway caught up with

him and handcuffed him. Sergeant Detective Terestre, who also

was unaware of the reason for the pursuit, gave the juvenile

Miranda warnings and asked him why he was running. Id. The

juvenile responded that he was running due to the contents of

the bag, and on a search of the bag, Terestre found numerous

plastic bags of marijuana. Id. The juvenile was arrested. Id.

"[T]he fact that the officers pursuing the juvenile were

not personally aware of the circumstances leading to the chase

is irrelevant." Roland R., 448 Mass. at 285. "In determining

whether police officers have reasonable suspicion for making a
 27

stop, 'the knowledge of each officer is treated as the common

knowledge of all officers' and must be examined to determine

whether reasonable suspicion exists." Id., quoting Richardson

v. Boston, 53 Mass. App. Ct. 201, 206 (2001).8

Roland R. illustrates the value and the practicality of

aggregating the knowledge of officers involved in a joint

effort. Frequently, officers must act quickly in an emergency

situation. Where multiple officers are on foot chasing a

suspect, they often do not have the luxury of communicating the

details of their knowledge leading up to the chase, or

"continuously" communicating regarding their shared objective.

8 I respectfully disagree with Justice Wendlandt that
Roland R. depicts facts more closely tailored to the vertical
collective knowledge doctrine, which, as she deems it, is
synonymous with the "fellow officer" rule. Post at .
Contrast Gittens, 211 A.D.2d at 245 ("A number of cases from the
Federal courts and other State courts, as well as a leading
treatise, have applied the fellow officer rule, which allows, in
essence, the imputation of knowledge from one officer to
another, to cover any number of officers working together on a
joint assignment despite the lack of an express communication of
information or direction to take action"). As she implicitly
recognizes, there was no verbal command to the acting officers
to arrest the defendant. Post at (acting officer acted on
the "non-verbal instruction to assist his fellow officers").
See Roland R., 448 Mass. at 280. It is true that in Roland R.,
one officer held the requisite reasonable suspicion on his own.
Id. at 284. It is unclear whether the acting officers were
"directed" to stop the juvenile. See id. at 285 (not specifying
whether Conway or Terestre heard radio call with description, or
whether description included directive to stop juvenile). Even
if Roland R. did not implicate the horizontal collective
knowledge doctrine, it illustrates the circumstances that
demonstrate its application.
 28

A stop should not be invalidated where there are sufficient

facts amounting to reasonable suspicion to stop a suspect simply

because the officer who is able to catch him or her was not

personally aware of all the information, and where that officer

is acting collaboratively with others who do have that

information, either in total or in part, but who did not have

the time to repeatedly communicate with the acting officer.

Continuing to apply the doctrine, in Commonwealth v. Quinn,

68 Mass. App. Ct. 476, 480 (2007), the Appeals Court imputed the

knowledge of one officer to another where they were acting in a

cooperative effort to investigate a break-in at a gasoline

station in the early hours of the morning. Officers Harvey and

Graham were the first to arrive at the gasoline station. Id. at

477. Harvey observed that the front door was "smashed," and

Graham radioed that there had been a break-in. Id. Both

officers saw two fresh sets of footprints in the snow leading

both toward and away from the gasoline station, which led to

fresh tire tracks heading toward a nearby highway. Id. Harvey

communicated this information over the radio. Id. Officer

Donahue, who was advised of the break-in but did not hear the

report of fresh tire tracks, drove south on the highway and then

doubled back, seeing a car heading away from the gasoline

station toward a rotary. Id. at 478. After radioing to the

other officers and confirming that no cars passed their
 29

location, he ultimately was able to catch up to the car and stop

it. Id. Donahue observed shards of glass, a baseball bat

covered with shards of glass, and a fresh cut on the driver's

hand; he arrested both occupants of the car. Id.

The Appeals Court imputed the knowledge of Harvey regarding

the fresh tire tracks and footprints to Donahue. Quinn, 68

Mass. App. Ct. at 480. "The officers were engaged in a

cooperative effort to investigate the break-in at the gasoline

station, so 'it is unnecessary for the detaining officer to know

all the information pertaining to the incident. . . . [T]he

knowledge of one [police officer] . . . [is] the knowledge of

all.'" Id. at 480-481, quoting Commonwealth v. Zirpolo, 37

Mass. App. Ct. 307, 311 (1994).9

Additionally, in Montoya, 464 Mass. at 576, the court

imputed the knowledge of one officer to another in holding that

police had probable cause to arrest the defendant. Troopers

Porter and Saunders were conducting surveillance in the parking

lot of a grocery store in separate, unmarked cars. Id. at 569.

Porter saw a pickup truck and sedan parked with the drivers'

windows facing each other and the drivers "hanging out of the

9Again, under the new rule, it is likely that this
information would not be aggregated. Was Donahue's radio
communication regarding passing cars enough to constitute
"continuous" communication between himself and Harvey and Graham
in order to aggregate their knowledge? The abstract nature of
this new rule will make it exceedingly difficult to apply.
 30

windows" and conversing. Id. Saunders saw the driver of the

sedan pass something to the driver of the truck, and Saunders

radioed this information to Porter. Id. Porter approached the

truck and saw the driver inhaling a substance through a glass

tube, and Porter informed Saunders about this observation over

the radio. Id. Saunders then stopped the sedan and arrested

the defendant, who was the driver. Id. The court "impute[d]

. . . to Saunders the knowledge of the buyer's admission to

Porter that he had just purchased the drugs, regardless of

whether that admission was immediately communicated by police

radio." Id. at 576, citing Roland R., 448 Mass. at 285.

Beyond the cases discussed supra, there are numerous other

Massachusetts opinions in which this court or the Appeals Court

either mentioned the collective knowledge doctrine or applied it

in a reasonable suspicion or probable cause context, without

relying on the content or extent of the communications between

the officers involved or the sufficiency of the "critical" facts

known to the acting officer. See Commonwealth v. Gullick, 386

Mass. 278, 283 (1982), S.C., 462 Mass. 1011 (2012) ("Troopers

Johnson, Ellis, and Mackin were engaged in a cooperative effort

in the investigation of this incident. We therefore evaluate

probable cause on the basis of the collective information of all

the officers"); Commonwealth v. Riggins, 366 Mass. 81, 88 (1974)

("Where a cooperative effort is involved, facts within the
 31

knowledge of one police officer have been relied on to justify

the conduct of another"); Commonwealth v. Chaisson, 358 Mass.

587, 590 (1971) ("The police were engaged in a cooperative

effort in radio-equipped cars. Hence the knowledge of one

officer is imputed to all officers"); Commonwealth v. Dyette, 87

Mass. App. Ct. 548, 555 n.10 (2015) ("The former municipal

police officer's knowledge of municipal trespass ordinances may

be imputed to his fellow officers"); Commonwealth v. Perez, 80

Mass. App. Ct. 271, 274 (2011) ("The knowledge of one officer is

part of 'the collective information' of other officers engaged

in the same cooperative effort" [citation omitted]);

Commonwealth v. Kotlyarevskiy, 59 Mass. App. Ct. 240, 243 (2003)

("Where, as here, the arresting officers are engaged in a

cooperative effort with other officers, probable cause is

evaluated on the basis of the collective information of all the

officers involved"); Commonwealth v. Peters, 48 Mass. App. Ct.

15, 18 (1999) ("These observations by [one officer],

communicated, and even if not, imputed to [the arresting

officer], reasonably led the officers to suspect that the

defendant had committed a crime" [emphasis added]); Commonwealth

v. Mendes, 46 Mass. App. Ct. 581, 589 (1999) ("The officers who

arrested the defendant were engaged in a cooperative effort with

the officers in the surveillance room on the ninth floor. We

therefore evaluate probable cause on the basis of the collective
 32

information of all the officers"); Zirpolo, 37 Mass. App. Ct. at

311 (applying collective knowledge doctrine in vertical context

based on arrest by officer who heard radio communication

providing probable cause); Garcia, 34 Mass. App. Ct. at 393 n.8

("Probable cause can be based upon the collective knowledge of

the police officers engaged in a joint effort"); Commonwealth v.

Andrews, 34 Mass. App. Ct. 324, 327 (1993) ("collective

knowledge of" two officers sufficient to support investigative

stop where one officer had detailed description of suspect's

shirt and other officer, who did not have that description,

stopped defendant); Commonwealth v. Scott, 29 Mass. App. Ct.

1004, 1006 (1990) ("While Officer Surridge's personal knowledge

may not have risen to the level of probable cause, other

officers present at the scene, also engaged in the effort to

apprehend the suspect, possessed additional information.

Probable cause may be based on the collective knowledge of

police officers when they are engaged in a cooperative effort");

Commonwealth v. Marlborough, 21 Mass. App. Ct. 944, 945 (1985)

("We are not concerned with the completeness of the information

possessed by each of the officers who collaborated in the search

and arrest. We evaluate probable cause on the basis of the

collective information of all the officers"); Commonwealth v.

Carrington, 20 Mass. App. Ct. 525, 529 n.4 (1985) ("The

Brookline, Newton and Boston officers were engaged in a
 33

cooperative effort in the investigation of this incident. When

an arrest is made in the course of such an investigation, the

knowledge of one police officer is attributable to all").

Here, the court limits the application of the collective

knowledge doctrine in order to prevent officers from making an

arrest "without probable cause simply because some other

officer, somewhere, has probable cause to arrest." Ante at ,

quoting State v. Ochoa, 131 Ariz. 175, 177 (Ariz. Ct. App.

1981). The court's discussion of the concerns of jurisdictions

that have required communication of the facts underlying

reasonable suspicion and probable cause do not support the new

rule enunciated here. See ante at . The court cites United

States v. Massenburg, 654 F.3d 480, 494 (4th Cir. 2011), where

the United States Court of Appeals for the Fourth Circuit stated

that the absence of a communication requirement could "create an

incentive for officers to conduct searches and seizures they

believe are likely illegal," merely "in the hopes that

uncommunicated information existed." See ante at . But the

court fails to explain how aggregating the knowledge of officers

working in a cooperative effort without regard to the extent or

content of their communications or the acting officer's precise

knowledge of critical facts, which we have done for over one-

half century, would encourage this behavior. The court does not

point to one case in which we have held that officers acted
 34

dishonestly by trying to pool information after a stop or an

arrest.10 Going even further, the court discusses concerns of

"reward[ing] police officers who were acting in bad faith,"

pointing to an example of an investigatory team finding

"sufficient probable cause or reasonable suspicion based on

information that had been learned after the stop." Ante at .

This would not occur when aggregating the knowledge of the

officers involved in a joint effort, because the knowledge of

the police at the time of the stop would be aggregated;

excluding any information learned after the stop or search. I

find it difficult to logically reach the court's conclusion.

I am mindful that Massachusetts has not adopted the "good

faith" exception to the exclusionary rule for purposes of art.

14; instead, we focus on whether violations are "substantial and

prejudicial." Commonwealth v. Hernandez, 456 Mass. 528, 533

(2010). Nonetheless, the principles underlying the exception

illustrate why the new rule, as set out by the court, likely

will have little to no deterrent effect. "The primary purpose

10In Hawkins, 361 Mass. at 386, the court declined to apply
the collective knowledge doctrine because the arresting officers
were not engaged in a cooperative effort with those who had
knowledge that the recovered bonds were stolen. Even there, the
arresting officers "admitted they had no actual knowledge that
the bonds had been stolen until after investigating their
ownership," foreclosing the argument that they were acting in
"bad faith." Id. The court recognized that "[t]he officers
here undoubtedly proceeded upon an honest belief that they were
acting within the law." Id. at 387.
 35

of the exclusionary rule is to deter future police misconduct by

barring, in a current prosecution, the admission of evidence

that the police have obtained in violation of rights protected

by the Federal and State Constitutions." Commonwealth v.

Santiago, 470 Mass. 574, 578 (2015). "The interest in deterring

unlawful police conduct, which is the foundation of the

exclusionary rule," is not implicated where an officer's conduct

is devoid of wrongdoing. Commonwealth v. Wilkerson, 436 Mass.

137, 142 (2002), quoting United States v. Janis, 428 U.S. 433,

454 (1976) (where "exclusionary rule does not result in

appreciable deterrence, then, clearly, its use . . . is

unwarranted").

The typical officer is acting in good faith, quickly, and

in concert with his fellow officers. Requiring the officer to

pause to assess the state of his knowledge in such circumstances

or to assess the level and content of his communication with his

fellow officers is an unrealistic, ineffective, and onerous

burden. Moreover, where exclusion has no deterrent effect,

"admission of the evidence is unlikely to encourage violations

of the Fourth Amendment." Janis, 428 U.S. at 458 n.35. See

United States v. Ragsdale, 470 F.2d 24, 31 (5th Cir. 1972)

("Unless we were to presume the unlikely possibility that an

officer would be encouraged to conduct an unlawful search on the

faint hope that his partner possessed probable cause, no proper
 36

purpose of [the exclusionary] rule would be served by denying to

justice the truth which this search disclosed").11

Even accepting that the new rule deters some police

misconduct, "it is apparent as a matter of logic that there is

little if any deterrence when the rule is invoked to suppress

evidence obtained by an officer acting in the reasonable belief

that his conduct did not violate" constitutional protections.

Illinois v. Gates, 462 U.S. 213, 260 (1983) (White, J.,

concurring).

"The deterrent purpose of the exclusionary rule necessarily
assumes that the police have engaged in willful, or at the
very least negligent, conduct which has deprived the
defendant of some right. By refusing to admit evidence
gained as a result of such conduct, the courts hope to
instill in those particular investigating officers, or in
their future counterparts, a greater degree of care toward
the rights of an accused. Where the official action was
pursued in complete good faith, however, the deterrence
rationale loses much of its force."

United States v. Peltier, 422 U.S. 531, 539 (1975), quoting

Michigan v. Tucker, 417 U.S. 433, 447 (1974). See, e.g., Brown

11Where officers are frequently uninformed of a judge's
decision or legal basis for granting a motion to suppress, the
"'deterrent safeguard' that is supposed to be provided by . . .
review of probable cause is imperfect." LaFave, supra at
§ 3.1(d), quoting Mapp v. Ohio, 367 U.S. 643 (1961).
"Obviously, police cannot be affirmatively influenced to change
their methods of law enforcement by the exclusion of evidence
when there is no communication to them of why the decision was
made." LaFave, supra, quoting LaFave & Remington, Controlling
the Police: The Judge's Role in Making and Reviewing Law
Enforcement Decisions, 63 Mich. L. Rev. 987, 1005 (1965). The
prosecutor is in the best position to communicate this to an
officer.
 37

v. Illinois, 422 U.S. 590, 610 (1975) (Powell, J., concurring)

("police normally will not make an illegal arrest in the hope of

eventually obtaining such a truly volunteered statement").

Maintaining the collective knowledge doctrine as we have

historically applied it will not encourage officers to act

without the requisite suspicion, where, as here, the acting

officer reasonably believes that he has sufficient information

to stop a suspect. For these reasons, the court is incorrect

that my approach would invite "post hoc rationalizations." Ante

at .

The court's decision today overturns years of consistent

and settled case law within Massachusetts. Contrast

Commonwealth v. Rossetti, 489 Mass. 589, 609 (2022) ("Where our

. . . jurisprudence does not currently reveal any settled or

consistent legal principles surrounding [the issue], we view our

decision today as departing only minimally from the principle of

stare decisis"). Because I think our steadfast application of

the collective knowledge doctrine to officers engaged in a

collaborative investigation is consistent with the protections

of art. 14, I would not do so.

Putting aside my agreement with the court that there was

reasonable suspicion to stop the defendant without resorting to

the collective knowledge doctrine, applying the doctrine as it

has been applied historically, Lieutenant (then Sergeant) Daryl
 38

Dwan's and Officer Luis Lopez's knowledge and observations would

be imputed to Doherty. All three officers were working as part

of a joint effort to apprehend the perpetrator of the armed

robbery that had occurred minutes prior. Doherty was listening

to the department radio channel, the same station on which the

description including the beard was broadcast, on which he heard

Dwan's updates about his observations on Morrissey Boulevard.

After hearing that, Doherty decided to canvas the Clam Point

area to search for the suspect. As soon as details of the armed

robbery were broadcast via the radio channel, Dwan began

canvassing Morrissey Boulevard. When Lopez heard the broadcast

reporting the armed robbery, he began driving around the area of

Victory Road, which he believed to be a potential flight path of

the suspect. Eventually, Dwan noticed the defendant, and

approached him at the same time as Doherty. Dwan described the

seizure and search of the defendant's backpack as a "joint

endeavor."

As the court concedes, ante at , the three officers were

engaged in a joint effort, sparked by communications on the

department radio channel, to discover the suspect. Thus, "'the

knowledge of each officer is treated as the common knowledge of

all officers' and must be examined to determine whether

reasonable suspicion exists." Roland R., 448 Mass. at 285,

quoting Richardson, 53 Mass. App. Ct. at 206. Applying the
 39

collective knowledge doctrine as it should be applied, in my

view, further bolsters reasonable suspicion.

Inserting a requirement that the officers be in "close and

continuous" communications with each other about a joint

objective and that the acting officer must have knowledge of at

least some of the critical facts eviscerates the horizontal

collective knowledge doctrine as it has been applied by

Massachusetts courts for over one-half century and replaces it

with a convoluted test that is problematic in its application.

Because I think that our jurisprudence regarding the collective

knowledge doctrine is supported by the general objectivity with

which we approach search and seizure law under art. 14, and by

practical considerations, I would not upend it.

I concur with the court's finding of reasonable suspicion,

but I respectfully dissent from the decision of the court

regarding the retreat from the collective knowledge doctrine.
 WENDLANDT, J. (concurring). We are called in this case, as

the United States Supreme Court was called in Terry v. Ohio, 392

U.S. 1, 4 (1968), to address "serious questions concerning the

role of the Fourth Amendment [to the United States Constitution

and art. 14 of the Massachusetts Declaration of Rights] in the

confrontation on the street between a[n individual] and the

police[ officer] investigating suspicious circumstances." In

Terry, the Court carved "a narrowly drawn authority" to permit

an officer to conduct a limited stop and patfrisk of an

individual based on reasonable suspicion -- a showing less than

that required to establish probable cause for a warrant. Id. at

27. This strictly circumscribed permission was designed to give

the officer on the scene "an escalating set of flexible

responses, graduated in relation to the amount of information"

possessed by the officer, during the "rapidly unfolding and

often dangerous situations" the officer faces, especially in the

nation's cities. Id. at 10.

In detailing this narrow ground for a stop, the Court

emphatically rejected the notion that the stop did not implicate

core constitutional concerns; "[i]t must be recognized that

whenever a police officer accosts an individual and restrains

his freedom to walk away, he has 'seized' that person" in a

constitutional sense. Id. at 16. A stop and subsequent

patfrisk of an individual "is a serious intrusion upon the
 2

sanctity of the person, which may inflict great indignity and

arouse strong resentment, and it is not to be undertaken

lightly." Id. at 17. Nonetheless, the Court recognized the

need to provide a level of flexibility to police activities,

which entail "necessarily swift action predicated upon the on-

the-spot observations of the officer on the beat" (emphasis

added). Id. at 20.

Balancing the nature of the invasion and the needs of law

enforcement officers to act upon the information they are

receiving in real time, the Court set forth the following

objective test to permit a warrantless stop: whether "the facts

available to the officer at the moment of the seizure . . .

[would] 'warrant a [person] of reasonable caution in the

belief'" that a crime had been, was being, or was about to be

committed (emphasis added). Id. at 21-22. In defining the

reasonable suspicion test, the Court noted that "[a]nything less

would invite intrusions upon constitutionally guaranteed rights

based on nothing more substantial than inarticulate hunches"

(emphasis added); and it remarked that a test based on good

faith alone would subject the people to the discretion of the

police, largely causing the constitutional protections to

"evaporate." Id. at 22. The genesis of this narrow police

authorization and the balance upon which it rests counsel that
 3

we reject the so-called horizontal collective knowledge doctrine

in all its varied forms.

The court today charts a different path, and there is some

good news and some bad. First, the good news: the court

rejects what it terms the "minority view" of the "horizontal

collective knowledge doctrine." Ante at . Under this legal

regime, the officer on the beat who detains you, pats you down,

and invades your personal autonomy by sliding hands up, down and

across your body in an ostensible search for weapons is not

considered to be acting as an individual human being. Instead,

the officer is part of "the" police -- a conceptual collective

"organism" apparently composed of a database of inculpatory

information about which the individual officer is entirely

ignorant at the time he or she stops and frisks you. The

officer's conduct is justified if somewhere in the dark recesses

of "the" police databank there exists information that can be

cobbled together post hoc to form the bare minimal showing

required for reasonable suspicion. The court rightly rejects

this police encounter of the third kind, and that is good news.

Now, the bad news: the court adopts what it terms the

"second approach" of the "horizontal collective knowledge"

doctrine. Ante at . Under this new order, the individual

officer is not part of a faceless, amorphous collective.

Instead, he or she is part of a "team" -- a finite set of
 4

officers "in close and continuous communication" with a "shared

objective." Ante at . The court adopts this version of the

horizontal collective knowledge doctrine, reasoning that,

despite all the advances in communications and surveillance

technology since Terry was decided, officers who are working as

a team on a shared mission and who are in constant contact

apparently can communicate "critical" facts but cannot be

expected to communicate the minimal information required for

reasonable suspicion. The stop and patfrisk are justified after

the fact if the facts constituting reasonable suspicion, while

uncommunicated, were known to one or more of the officers on the

team –- in short, an officer on the beat can detain and pat

frisk you based on a hunch, in the hopes that afterward fellow

officers can fill in the missing gaps in the reasonable

suspicion calculus.

In assessing the merits of the court's approach, it is

important to remember that reasonable suspicion is, by design,

not a high hurdle; it is something less than probable cause. It

can be based on information as to which the acting officer has

personal knowledge -- information based on the officer's own

observations gathered through the use of his or her own senses.

It can also be grounded in information acquired from third

parties or other sources of reliable information, whether from

911 calls, police dispatchers, police bulletins, confidential
 5

informants, or fellow officers. And the acting officer may draw

reasonable inferences and pull on his or her years of experience

in assessing the evolving situation.

Holding a law enforcement officer to this bare minimal

standard even when he or she is working jointly with others

before permitting the officer to intrude on the sanctity of the

person does not ignore, as the court surmises, the "practical

reality of effective law enforcement." Ante at . Indeed, it

was the recognition of the realities of fast-paced, on the

street encounters that was the genesis of the reasonable

suspicion standard -– a standard that represents the Court's

careful calibration between the nature of the invasion of the

rights of the individual, on the one hand, and the undeniable

needs of law enforcement to urgently respond to suspected

criminal activity and potentially dangerous situations, on the

other. The Court in Terry set a constitutional floor –- a

baseline that we certainly should not (and in my view cannot)

abandon under the auspices of art. 14 of our State Constitution.

1. Fellow officer rule. Notably, this case does not

concern the fellow officer rule, what the court terms the

"vertical" collective knowledge doctrine. Under this rule, the

acting officer may assist a fellow officer by executing a Terry-

type stop in reliance that the directing officer had a

constitutional basis for the stop; in such a case, whether the
 6

stop passes constitutional muster will depend on whether the

directing officer had the information constituting reasonable

suspicion. See United States v. Hensley, 469 U.S. 221, 231

(1985), quoting United States v. Robinson, 536 F.2d 1298, 1299

(9th Cir. 1976) ("effective law enforcement cannot be conducted

unless police officers can act on directions and information

transmitted by one officer to another and . . . officers, who

must often act swiftly, cannot be expected to cross-examine

their fellow officers about the foundation for the transmitted

information"); Whiteley v. Warden, Wyo. State Penitentiary, 401

U.S. 560, 568 (1971) ("police officers called upon to aid other

officers in executing arrest warrants are entitled to assume

that the officers requesting aid offered the magistrate the

information requisite to support an independent judicial

assessment of probable cause").

The fellow officer rule is "a matter of common sense: the

rule minimizes the volume of information concerning suspects

that must be transmitted to other jurisdictions or officers and

enables police to act promptly in reliance on information from

another jurisdiction or officer" (alterations omitted). United

States v. Massenburg, 654 F.3d 480, 494 (4th Cir. 2011), quoting

Hensley, 469 U.S. at 231. Thus, the fellow officer rule "simply

directs us to substitute the knowledge of the instructing

officer or officers for the knowledge of the acting officer."
 7

Massenburg, supra at 493. See 2 W.R. LaFave, Search and Seizure

§ 3.5(b), at 333 (6th ed. 2020) ("Thus, under the Whiteley rule

[or, as it is sometimes termed, the 'fellow officer' rule]

police are in a limited sense 'entitled to act' upon the

strength of a communication through official channels directing

or requesting than an arrest or search be made" [citations

omitted]).1

2. Horizontal collective knowledge doctrine. Unlike the

fellow officer rule, which is a commonsense response to the

oftentimes quickly unfolding events officers encounter and

allows the acting officer to rely on the verbal (or nonverbal,

see note 1, supra) directions relayed by fellow officers, the

horizontal collective knowledge doctrine is anathema to the

Fourth Amendment and art. 14. Even under the version of the

"second approach" to the horizontal collective knowledge

doctrine adopted by the court, it permits an officer to stop

(and presumably pat frisk) an individual without beforehand

1 In Commonwealth v. Roland R., 448 Mass. 278, 280 (2007),
for example, the acting officer stopped the juvenile after
seeing fellow officers chasing him at the direction of an
instructing officer, who had the requisite information
constituting reasonable suspicion. Although the court stated
that its conclusion rested on the horizontal collective
knowledge doctrine, id. at 285, the facts fall within the fellow
officer rule -- namely, that the acting officer acted upon
seeing the chase, a nonverbal instruction to assist his fellow
officers, who were chasing the juvenile at the order of the
directing officer who, in turn, had the requisite reasonable
suspicion. Id. at 280.
 8

having information constituting reasonable suspicion and without

any commonsense reliance on a fellow officer's directions;

shockingly, it invites a judge to be complicit in the unraveling

of this fundamental constitutional right. See Terry, 392 U.S.

at 9, quoting Union Pac. Ry. Co. v. Botsford, 141 U.S. 250, 251

(1891) ("No right is held more sacred, or is more carefully

guarded, by the common law, than the right of every individual

to the possession and control of his own person, free from all

restraint or interference of others, unless by clear and

unquestionable authority of law").

The doctrine rests on the hope that, post hoc, a judge will

cobble together information known to other officers on the team

-- information as to which the acting officer is entirely

ignorant and has no basis to believe is known to a fellow

officer -- to constitute the minimal requirement of reasonable

suspicion for the stop. It is divorced entirely from the

urgency that birthed the limited nature of the Terry-type stop

and frisk -– namely, that the officer at the scene, the one

facing the exigencies attendant thereto, needs to be able to

rely on the rapidly unfolding information known to him or her as

well as the "reasonable inferences which [the officer] is

entitled to draw from the facts in light of his [or her]

experience." Terry, 392 U.S. at 27. And it jettisons the

careful balance struck by the Court in defining the reasonable
 9

suspicion standard, between the right to be free from

governmental restraint and the attendant serious intrusion on

the sanctity of the person, on the one hand, and the needs of

the law enforcement officer on the street to be able to quickly

react to the information being received and to draw reasonable

inferences from that information consistent with his or her

experience, on the other. Id. at 21-22.

The few cases that provide a rationale for adopting the

horizontal collective knowledge doctrine sacrifice this careful

balance apparently on the same assumption driving the court's

decision today -- namely, that officers working as a team in

close and continuous communication can communicate some

"critical facts," but cannot be expected communicate the minimal

information constituting reasonable suspicion during the course

of the fast-paced, dynamically evolving events on the ground.

See, e.g., United States v. Cook, 277 F.3d 82, 86 (1st Cir.

2002) ("Investigative stops generally occur in a dynamic

environment marked by the potential for violence. Officers who

jointly make such stops rarely will have an opportunity to

confer during the course of the stop"). Contrary to this

distorted view of the balance struck by the Supreme Court in

Terry, adherence to the reasonable suspicion standard would not

require officers in hot pursuit of a suspect to "stop and

confer" or to convene a "conference" while permitting the
 10

suspect to flee. Ante at . Obviously, officers could employ

any and all methods of communication, including, for example,

those used to relay the "critical facts" constituting those

minimally required to rise to the level of reasonable suspicion.

But if the acting officer lacks information required for

reasonable suspicion, the officer's conduct falls below the

Supreme Court's carefully constructed constitutional floor -- it

is unguided by any constitutional norms. See United States v.

Ross, 456 U.S. 798, 824-825 (1982), quoting Mincey v. Arizona,

437 U.S. 385, 390 (1978) ("searches conducted outside the

judicial process, without prior approval by judge or magistrate,

are per se unreasonable under the Fourth Amendment -- subject

only to a few specifically established and well-delineated

exceptions").

Perversely, because the acting officer is totally ignorant

as to whether information constituting reasonable suspicion

exists, the horizontal collective knowledge doctrine provides

incentive to the acting officer to roll the dice and stop an

individual knowing that reasonable suspicion is absent, on the

off chance that other information unbeknownst to him or her

might supply the gaps missing in the reasonable suspicion

calculus. See Massenburg, 654 F.3d at 494 (horizontal

collective knowledge doctrine "would only create an incentive

for officers to conduct search and seizures they believe are
 11

likely illegal," which is "directly contrary to the purposes of

longstanding Fourth Amendment jurisprudence"). In short, the

doctrine represents the feared "[a]nything less," which the

Supreme Court rightly predicted "would invite intrusions upon

constitutionally guaranteed rights based on nothing more

substantial than inarticulate hunches." Terry, 392 U.S. at 22.

Like the United States Courts of Appeals for the Second,

Fourth, and Tenth Circuits, I can find nothing to commend the

doctrine and accordingly reject it. See Massenburg, 654 F.3d at

494-495 ("Though we have studied our sister circuits' cases

adopting an aggregation rule, we can find no convincing defense

of it. . . . Because we believe the aggregation rule runs

contrary to the Supreme Court's Fourth Amendment jurisprudence,

would seriously erode the efficacy of the exclusionary rule's

deterrent purposes, and serves none of the legitimate ends of

law enforcement, we reject it"). See also United States v.

Hussain, 835 F.3d 307, 316 n.8 (2d Cir. 2016) ("Absent record

evidence that [the first officer] communicated his suspicion or

any relevant information to [the acting officer] before the

latter began to conduct the protective search, we will not

impute his knowledge or reasonable suspicion to [the acting

officer] under the doctrine of collective knowledge. . . . [W]e

decline to extend the collective knowledge doctrine to cases

where, as here, there is no evidence that an officer has
 12

communicated his suspicions with the officer conducting the

search, even when the officers are working closely together at a

scene"); United States v. Whitley, 680 F.3d 1227, 1234 n.3 (10th

Cir. 2012), quoting United States v. Chavez, 534 F.3d 1338, 1345

(10th Cir. 2008), cert. denied, 555 U.S. 1121 (2009) (confirming

requirement that individual officers "have communicated the

information they possess individually" to arresting officer ex

ante); United States v. Shareef, 100 F.3d 1491, 1503-1505 (10th

Cir. 1996) (no constitutional basis for arrest where officers

did not actually communicate information constituting probable

cause to one another, either verbally or nonverbally, ex ante).

To be sure, like the court here, ante at , two of these

Federal courts -- the Second and Tenth Circuits -- themselves

use the "collective knowledge" language such as "imputed" or

"aggregated" information in describing their approach; it is an

unfortunate misuse of the terminology. Instead, the courts in

these jurisdictions conclude that the acting officer may rely on

information communicated to him or her by other officers or

sources and that he or she need not have personally observed the

information; but the acting officer must have had this

information, whether from his or her direct observations or from

what had been communicated to him or her, ex ante, before the

stop and patfrisk were initiated. See Hussain, 835 F.3d at 316

n.8; Chavez, 534 F.3d at 1345.
 13

In other words, the rules of evidence, which generally

limit a witness to testifying to information as to which he or

she has personal knowledge, and which traditionally govern

admissibility of evidence in our court rooms, do not limit the

scope of the information an officer on the beat may rely upon in

assessing the rapidly unfolding situation he or she encounters

on the street. See, e.g., Commonwealth v. Manha, 479 Mass. 44,

47-48 (2018) (reasonable suspicion to conduct Terry-type stop

and patfrisk based on reliable information from anonymous 911

caller but as to which acting officer lacked personal

knowledge); Commonwealth v. Mercado, 422 Mass. 367, 369 (1996)

(reasonable suspicion to conduct Terry-type stop based, in part,

on information conveyed in radio bulletin and by witness but as

to which officer lacked personal knowledge). See also United

States v. Blair, 524 F.3d 740, 751 (6th Cir. 2008) (noting

"unremarkable proposition that one officer may conduct a Terry[-

type] stop based on the information obtained from another

officer"). Because those evidentiary rules do not govern the

reasonable suspicion analysis, I see no need to adopt any

version of the horizontal collective knowledge doctrine on the

basis of their application. See Terry, 392 U.S. at 21-22

(officer may rely on facts sufficient to "warrant a man of

reasonable caution in the belief" that crime had been, was

being, or was about to be committed).
 14

Indeed, the Cartesian terminology, in my view, is entirely

unhelpful and has led to widespread confusion. See ante

at (describing "vertical" collective knowledge doctrine;

"first approach" to horizontal collective knowledge doctrine

requiring ex ante communication of facts constituting reasonable

suspicion to acting officer; exception to first approach;

"second approach" to horizontal collective knowledge doctrine;

"minority view" of horizontal collective knowledge doctrine; and

numerous other variations thereof).

The rule should be, and under Terry must be, this: one

officer, whether it is the officer who directs the acting

officer to stop the suspect (i.e., the fellow officer rule, see

discussion and note 1, supra) or the acting officer him- or

herself, must have the information constituting reasonable

suspicion -- whether it is information as to which the officer

has personal knowledge or information he or she has been told --

before the stop and patfrisk are conducted. This is the

constitutional balance struck by Terry and its progeny between

the rights of the individual to be free from unreasonable

searches and seizures and the need to accommodate the law

enforcement realities of the quickly unfolding events on the

ground.

Laudably, the court rejects the more extreme version of the

horizontal collective knowledge doctrine, which treats the
 15

police as an "organism" with unfettered access to a database of

inculpatory information that can be accessed post hoc to justify

an otherwise unconstitutional stop and patfrisk. See Shareef,

100 F.3d at 1504 & n.6. The court today cabins its version of

the horizontal collective knowledge doctrine, concluding that it

applies only in situations where officers are involved in a

joint investigation with a mutual purpose and objective and in

close and continuous communication with each other about that

objective, and the acting officer has knowledge "of at least

some of the critical facts." Ante at . But the court does

not explain why an officer who knows the "critical" facts cannot

be expected to know the facts constituting reasonable suspicion,

which itself is a low bar. See generally 4 LaFave, supra at

§ 9.5(b) at 672-691 (comparing reasonable suspicion and probable

cause). Although to a lesser extent than the unbridled adoption

of the "minority view" of the horizontal collective knowledge

doctrine might be, the adopted approach is the proverbial

camel's nose under the tent. It threatens individuals with

unconstitutional intrusions on their persons, inflicting great

indignity and arousing strong resentment, all the while

requiring judges to condone this behavior in connection with

their hindsight review.

3. Inevitable discovery exception. The court adopts its

version of the horizontal collective knowledge doctrine
 16

apparently out of the concern that rejecting the horizontal

collective knowledge doctrine would "make[] little sense from a

practical standpoint" because it would "[b]as[e] the legitimacy

of the stop solely on what the officer who first approaches the

suspect knows." Ante at , quoting Cook, 277 F.3d at 86.

However, if the first officer acts too swiftly but a second

officer has reasonable suspicion, our existing inevitable

discovery doctrine permits the use of the evidence at trial as

an exception to the exclusionary rule. See United States v.

Ragsdale, 470 F.2d 24, 30 (5th Cir. 1972) (exclusionary rule

does not apply when search "would imminently and lawfully have

been made and [the evidence would have been] discovered at this

very time and place and by this team of officers" if acting

officer had waited); United States v. Gorham, 317 F. Supp. 3d

459, 474 (D.D.C. 2018), quoting 2 W.R. LaFave, Search and

Seizure § 3.5(c) (5th ed. Supp. Oct. 2017) ("Unlike in the

typical 'horizontal' collective knowledge case, Ragsdale does

not require a post hoc aggregation of information among

officers; rather, an officer with all the required information

was present and 'it is clear the search would imminently and

lawfully have been made'").

Under this long-standing doctrine:

"if the government can prove that the evidence would have
been obtained inevitably and, therefore, would have been
admitted regardless of any overreaching by the police,
 17

there is no rational basis to keep that evidence from the
jury in order to ensure the fairness of the trial
proceedings. In that situation, the State has gained no
advantage at trial and the defendant has suffered no
prejudice. Indeed, suppression of the evidence would
operate to undermine the adversary system by putting the
State in a worse position than it would have occupied
without any police misconduct."

Nix v. Williams, 467 U.S. 431, 447 (1984). See id. at 448-449

(declining to apply exclusionary rule when "volunteer search

party would ultimately or inevitably have discovered the

victim's body"). The doctrine provides that evidence that would

otherwise have been excluded is admissible nonetheless if the

Commonwealth demonstrates by a preponderance of the evidence

"that discovery of the evidence by lawful means was certain as a

practical matter, 'the officers did not act in bad faith to

accelerate the discovery of evidence, and the particular

constitutional violation is not so severe as to require

suppression.'" Commonwealth v. Hernandez, 473 Mass. 379, 386

(2015), quoting Commonwealth v. Sbordone, 424 Mass. 802, 810

(1997) (no exclusion of handgun found in course of unlawful

search of trunk because there would have been reasonable

suspicion after subsequent showup identification). Thus, our

long-standing jurisprudence based on the inevitable discovery

doctrine provides a commonsense approach to assuage the fear
 18

undergirding the court's adoption of its version of the

horizontal collective knowledge doctrine.2

4. Reasonable suspicion. Despite the foregoing, I concur

in the judgment because Officer Brian Doherty had the requisite

reasonable suspicion; I do so, however, without imputing any of

Lieutenant (then Sergeant) Daryl Dwan's uncommunicated

information. In other words, Doherty, even without the

information concerning the suspect's facial hair, had reasonable

suspicion to stop the defendant.

Briefly, at the time Doherty stopped the defendant, he knew

that an armed robbery had been committed a little after

3:30 A.M. The grave nature of the crime and the imminent danger

presented by the suspect on the loose in the neighborhood

properly may be considered in the reasonable suspicion calculus.

See Commonwealth v. Henley, 488 Mass. 95, 104 (2021), quoting

Commonwealth v. Depina, 456 Mass. 238, 247 (2010) ("The gravity

of the crime and the present danger of the circumstances may be

considered in the reasonable suspicion calculus"); Commonwealth

2 Of course, as the court notes, ante at , the inevitable
discovery doctrine may not apply where a second officer both has
been unable to communicate information to the acting officer and
is not at the scene of the stop and patfrisk. In such a
scenario, the acting officer lacks reasonable suspicion; we
ought not permit him or her to get by the meager constitutional
hurdle -- the one set by the Supreme Court in Terry as the
constitutionally mandated minimal standard -- with a little help
from his or her silent and distant friends.
 19

v. Evelyn, 485 Mass. 691, 705 (2020) ("circumstances indicated a

potential ongoing risk to public safety and therefore weighed in

favor of reasonable suspicion").

Doherty also had, at a minimum, heard the first transmitted

description of the suspect of the armed robbery as a Black man

in his late twenties, who was between five foot seven and five

foot eight, wearing jeans, and walking toward a pharmacy, and

then had seen that the defendant largely matched this

description. See Commonwealth v. Meneus, 476 Mass. 231, 236

(2017), quoting Commonwealth v. Lopes, 455 Mass. 147, 158 (2009)

("We have no hard and fast rule governing the required level of

particularity of a description; our constitutional analysis

ultimately is practical, balancing the risk that an innocent

person will be needlessly stopped with the risk that a guilty

person will be allowed to escape" [alterations omitted]).

Doherty also saw the defendant in close temporal and

geographic proximity to the scene of the armed robbery, which

had occurred just seven minutes prior to him encountering the

defendant. See Commonwealth v. Warren, 475 Mass. 530, 536

(2016) ("proximity of the stop to the time and location of the

crime is a relevant factor in the reasonable suspicion

analysis").

It was dark and raining, and Doherty did not see anyone

else in the area surrounding the crime scene as he canvassed
 20

various streets in the area for approximately four to six

minutes following the report of the crime. He was aware of

Dwan's report that Dwan was on Morrisey Boulevard and also had

not seen anyone. Thus, not only did the defendant fit the

general description of the suspect, but the defendant was the

only person near the scene of the crime within seven minutes of

its occurrence. See Evelyn, 485 Mass. at 704-705 (reasonable

suspicion without any description when "officers encountered the

defendant thirteen minutes after the shooting, one-half mile

distant from it" on "a cold night, and the officers had not seen

any other pedestrians on the nearby streets"). Compare Warren,

475 Mass. at 536 (no reasonable suspicion based on general

description for defendant found twenty-five minutes later,

approximately one mile from scene of crime), with Henley, 488

Mass. at 104 (reasonable suspicion based on general description

for defendant found five minutes later, two blocks from scene of

crime), and Depina, 456 Mass. at 246 (reasonable suspicion based

on general description when defendant, "approximately ten

minutes after the report of the shooting, was seen within three

blocks of the crime scene, and he was moving away from the area

of the shooting"). See also Warren, supra, citing Commonwealth

v. Doocey, 56 Mass. App. Ct. 550, 555 n.8 (2002) ("Proximity is

accorded greater probative value in the reasonable suspicion

calculus when the distance is short and the timing is close").
 21

Finally, Doherty knew that the defendant was in the

reported flight path of the suspect and that that path included

a hole in the fence between the crime scene and the location

where he found the defendant. See Warren, 457 Mass. at 536-538,

citing Commonwealth v. Foster, 48 Mass. App. Ct. 671, 672-673,

676 (2000) (whether defendant is found in direction of flight

path relevant to reasonable suspicion).

Considering the totality of the circumstances,3 it was

reasonable for Doherty to stop the defendant. Accordingly, I

concur in the judgment.

3 Even if no one factor results in the necessary
individualized suspicion, considered in combination, several
factors "may allow the police to narrow the range of suspects to
[a] particular individual[]." Mercado, 422 Mass. at 371. See
id. (circumstances giving rise to reasonable suspicion must be
such as to "distinguish [the defendant] from other persons in
the vicinity").