2021 WI 68
SUPREME COURT OF WISCONSIN
CASE NO.: 2019AP1404-CR
COMPLETE TITLE: State of Wisconsin,
Plaintiff-Respondent,
v.
George Steven Burch,
Defendant-Appellant.
ON CERTIFICATION FROM THE COURT OF APPEALS
OPINION FILED: June 29, 2021
SUBMITTED ON BRIEFS:
ORAL ARGUMENT: April 12, 2021
SOURCE OF APPEAL:
COURT: Circuit
COUNTY: Brown
JUDGE: John Zakowski
JUSTICES:
HAGEDORN, J., delivered the majority opinion of the Court, in
which ZIEGLER, C.J, ROGGENSACK, and REBECCA GRASSL BRADLEY, JJ.,
joined, and in which DALLET and KAROFSKY, JJ., joined with
respect to Parts I. and II.B. REBECCA GRASSL BRADLEY, J., filed
a concurring opinion. DALLET, J., filed an opinion concurring
in part and dissenting in part, in which KAROFSKY, J., joined
and in which ANN WALSH BRADLEY, J., joined except for footnote
1. ANN WALSH BRADLEY, J., filed a dissenting opinion.
NOT PARTICIPATING:
ATTORNEYS:
For the defendant-appellant, there were briefs filed by Ana
L. Babcock and Babcock Law, LLC. There was an oral argument by
Ana L. Babcock.
For the plaintiff-respondent, there was a brief filed by
Aaron R. O’Neil, assistant attorney general; with whom on the
brief was Joshua L. Kaul, attorney general. There was an oral
argument by Aaron R. O’Neil.
An amicus curiae brief was filed on behalf of Legal Action
of Wisconsin, Inc. by Rebecca M. Donaldson, Milwaukee.
2
2021 WI 68
NOTICE
This opinion is subject to further
editing and modification. The final
version will appear in the bound
volume of the official reports.
No. 2019AP1404-CR
(L.C. No. 2016CF1309)
STATE OF WISCONSIN : IN SUPREME COURT
State of Wisconsin,
Plaintiff-Respondent, FILED
v. JUN 29, 2021
George Steven Burch, Sheila T. Reiff
Clerk of Supreme Court
Defendant-Appellant.
HAGEDORN, J., delivered the majority opinion of the Court, in
which ZIEGLER, C.J, ROGGENSACK, and REBECCA GRASSL BRADLEY, JJ.,
joined, and in which DALLET and KAROFSKY, JJ., joined with
respect to Parts I. and II.B. REBECCA GRASSL BRADLEY, J., filed
a concurring opinion. DALLET, J., filed an opinion concurring
in part and dissenting in part, in which KAROFSKY, J., joined
and in which ANN WALSH BRADLEY, J., joined except for
footnote 1. ANN WALSH BRADLEY, J., filed a dissenting opinion.
APPEAL from a judgment of the Circuit Court for Brown
County. Affirmed.
¶1 BRIAN HAGEDORN, J. George Steven Burch appeals a
judgment of conviction for first-degree intentional homicide on
the grounds that two pre-trial evidentiary motions were
incorrectly denied.
No. 2019AP1404-CR
¶2 First, relying on the Fourth Amendment, Burch moved to
suppress the admission of incriminating cell phone data. This
data was obtained via an unrelated criminal investigation and
kept in a police database. A different law enforcement agency
investigating the homicide came upon this data and used it to
connect Burch to the homicide. Burch argues that the initial
download of the data exceeded the scope of his consent, the data
was unlawfully retained, and the subsequent accessing of the
data violated his reasonable expectation of privacy. We
conclude that even if some constitutional defect attended either
the initial download or subsequent accessing of the cell phone
data, there was no law enforcement misconduct that would warrant
exclusion of that data. Therefore, we conclude the circuit
court correctly denied Burch's motion to suppress that data.
¶3 Regarding the second pre-trial evidentiary motion,
Burch asks us to reverse the circuit court's discretionary
decision to admit evidence from a Fitbit device allegedly worn
by the victim's boyfriend at the time of the homicide. This
evidence, Burch maintains, should have been accompanied by
expert testimony and was insufficiently authenticated. We agree
with the State that the circuit court's decision to admit this
evidence was not an erroneous exercise of discretion. Burch's
judgment of conviction is affirmed.
I. BACKGROUND
¶4 On May 20, 2016, Nicole VanderHeyden went to a bar
with her boyfriend, Douglass Detrie. The two became separated
2
No. 2019AP1404-CR
and, in the course of a subsequent phone call and text messages,
got into an argument. Detrie returned alone to their shared
home. The next day, VanderHeyden's body was discovered next to
a nearby field. Her blood-stained clothing was later found
discarded alongside a freeway on-ramp, and some of her blood and
hair were identified outside the house of VanderHeyden's
neighbor. The Brown County Sheriff's Office (the "Sheriff's
Office") opened a homicide investigation that spanned the next
several months. Detrie was initially a suspect, but the focus
of the investigation shifted away from Detrie in part because
his Fitbit device logged only 12 steps during the hours of
VanderHeyden's death.1
¶5 While the Sheriff's Office investigated VanderHeyden's
homicide, the Green Bay Police Department (the "Police
Department") undertook an unrelated investigation into three
incidents involving the same vehicle——a stolen vehicle report, a
vehicle fire, and a hit-and-run. George Burch was a suspect in
this investigation, and Police Department Officer Robert
Bourdelais interviewed him on June 8, 2016. Burch denied
involvement and offered the alibi that he was at a bar that
night and texting a woman who lived nearby. As Officer
Bourdelais testified, "I asked [Burch] if I could see the text
messages between him and [the woman], if my lieutenant and I
could take a look at his text messages." Burch agreed. Officer
Detrie wore a Fitbit Flex, a wrist-worn device that
1
continuously tracks the wearer's steps and interfaces with the
wearer's phone or computer.
3
No. 2019AP1404-CR
Bourdelais then explained that he preferred to download
information off the phone because "it's a lot easier to do that
than try to take a bunch of pictures and then have to scan those
in." "So I asked him if he would be willing to let me take his
phone to this detective, download the information off the phone
and then I'd bring the phone right back to him . . . and he said
that would be fine."
¶6 Before Officer Bourdelais took the phone to be
downloaded, Burch signed a consent form. The form read: "I
George Stephen Burch . . . voluntarily give Det. Danielski,
Officer Bourdelais or any assisting personnel permission to
search my . . . Samsung cellphone." Officer Bourdelais took the
phone and the signed consent form to the certified forensic
computer examiner for the Police Department. The forensic
expert performed a "physical extraction" of all the data on
Burch's phone, brought the data into a readable format, and
saved the extraction to the Police Department's long-term
storage. At a motion hearing, the forensic expert testified
that this was consistent with the Police Department's standard
practice.
¶7 Two months later, two Sheriff's Office detectives
continuing the investigation of VanderHeyden's homicide matched
a DNA sample from VanderHeyden's sock to Burch. The detectives
then searched their own department's records and the records of
other local departments for prior police contacts with Burch.
There they discovered the Police Department's file related to
the three vehicle-related incidents. The file included Burch's
4
No. 2019AP1404-CR
signed consent form and a copy of the data the Police Department
extracted from Burch's phone during the search. It also
contained a narrative written by Officer Bourdelais which
indicated Burch said Officer Bourdelais "could take his phone to
the department to have the information on it downloaded."
Nothing in the consent form, the narrative, or anything else in
the file, indicated that Burch limited the scope of the data he
consented to have downloaded from his phone.
¶8 The Sheriff's Office detectives reviewed the data
downloaded from Burch's phone. They noted that Burch's internet
history included 64 viewings of news stories about
VanderHeyden's death. And they also discovered Burch had an
email address associated with a Google account. In light of
this discovery, the Sheriff's Office detectives procured a
search warrant to obtain the "Google Dashboard" information from
Google corresponding to Burch's email address. The data Google
provided contained location information that placed Burch's
phone at a bar VanderHeyden visited the night of her death, a
location near VanderHeyden's residence, the place where
VanderHeyden's body was found, and the on-ramp where
VanderHeyden's discarded clothing was discovered.
¶9 Burch was arrested and charged with VanderHeyden's
death. He filed two pre-trial evidentiary motions relevant to
this appeal.
¶10 In one motion, Burch sought to suppress the data
obtained from his cell phone for two reasons: (1) the Police
Department's extraction of the data exceeded the scope of
5
No. 2019AP1404-CR
Burch's consent by obtaining all the phone's data, rather than
just the text messages; and (2) the Sheriff's Office unlawfully
accessed the data in August 2016. The circuit court2 denied
Burch's motion. It concluded that the conversation between
Burch and Officer Bourdelais did not limit the scope of Burch's
consent, and that "the sharing of such information, without
first obtaining a warrant, is a common and long-understood
practice between related departments."
¶11 Burch also moved to exclude evidence related to
Detrie's Fitbit device. He argued the State must produce an
expert to establish the reliability of the science underlying
the Fitbit device's technology and that the State failed to
sufficiently authenticate the records. The circuit court
disagreed and refused to exclude the Fitbit evidence related to
step-counting.3
¶12 Burch testified in his own defense at trial. He
denied killing VanderHeyden, but acknowledged he was with her
the night she died. According to Burch, he met VanderHeyden at
a bar, and the two left together. After parking near
VanderHeyden's house, they became intimate. That, Burch said,
was the last thing he remembered before waking up on the ground
with Detrie there, and VanderHeyden dead. Burch told the jury
that Detrie held him at gunpoint and instructed him to move
2 The Honorable John P. Zakowski of the Brown County Circuit
Court presided.
3 The circuit court granted Burch's motion in part, agreeing
to exclude Fitbit evidence related to sleep-monitoring.
6
No. 2019AP1404-CR
VanderHeyden's body into his vehicle, drive to a field, and
carry VanderHeyden's body into the ditch. Only then did Burch
escape by pushing Detrie, running back to his vehicle, and
driving away. Burch added that on his way home he noticed that
articles of VanderHeyden's clothing were still in his vehicle
and threw them out the window in a panic. In the months that
followed, Burch told no one this version of events, even as
authorities sought the public's help in solving VanderHeyden's
homicide.
¶13 The jury found Burch guilty of first-degree
intentional homicide, and the circuit court sentenced him to
life in prison. Burch appealed, challenging the circuit court's
denial of his motion to suppress the cell phone data and his
motion to exclude the Fitbit evidence. The court of appeals
certified the case to us, and we accepted the certification.
II. DISCUSSION
A. Cell Phone Data
¶14 Burch asks us to reverse the circuit court's denial of
his motion to suppress the cell phone data as contrary to the
Fourth Amendment. The Fourth Amendment protects the "right of
the people to be secure in their persons, houses, papers, and
effects, against unreasonable searches and seizures." U.S.
Const. amend. IV. On review of a circuit court's denial of a
suppression motion, we uphold the circuit court's findings of
historical fact unless they are clearly erroneous, and
independently apply constitutional principles to those facts.
7
No. 2019AP1404-CR
State v. Robinson, 2010 WI 80, ¶22, 327 Wis. 2d 302, 786
N.W.2d 463.
¶15 Before us, Burch argues the cell phone data was
obtained in violation of the Fourth Amendment for three reasons:
(1) the Police Department obtained the data without his consent;
(2) the Police Department unlawfully retained the data after its
investigation into the vehicle-related incidents had ended; and
(3) the Sheriff's Office unlawfully accessed the data in the
Police Department's records without a warrant.4 However, for the
reasons that follow, regardless of whether the data was
unlawfully obtained or accessed, we conclude suppression of the
data is not warranted under the exclusionary rule. See Herring
v. United States, 555 U.S. 135, 139 (2009) (accepting the
"assumption that there was a Fourth Amendment violation" and
analyzing whether the exclusionary rule applied); see also State
v. Kerr, 2018 WI 87, ¶¶20-24, 383 Wis. 2d 306, 913 N.W.2d 787.
1. The Exclusionary Rule
¶16 "When there has been an unlawful search, a common
judicial remedy for the constitutional error is exclusion."
State v. Dearborn, 2010 WI 84, ¶15, 327 Wis. 2d 252, 786
4Burch forfeited his argument related to the Police
Department's retention of the cell phone data by not raising
that argument before the circuit court. See State v. Huebner,
2000 WI 59, ¶10, 235 Wis. 2d 486, 611 N.W. 2d 727. His
arguments regarding the initial download of the data and the
subsequent accessing of the data are, however, properly before
us.
8
No. 2019AP1404-CR
N.W.2d 97. The exclusionary rule is a judicially-created,
prudential doctrine designed to compel respect for the Fourth
Amendment's constitutional guaranty. Davis v. United States,
564 U.S. 229, 236 (2011). In recent years, the United States
Supreme Court has significantly clarified the purpose and proper
application of the exclusionary rule. See id.; Herring, 555
U.S. 135. In Davis, the Supreme Court explained that prior
cases suggested that the exclusionary rule "was a self-executing
mandate implicit in the Fourth Amendment itself." 564 U.S. at
237. However, more recent cases have acknowledged that the
exclusionary rule is not one of "reflexive" application, but is
to be applied only after a "rigorous weighing of its costs and
deterrence benefits." Id. at 238. Thus, in both Herring and
Davis, the Court explained that to "trigger the exclusionary
rule, police conduct must be sufficiently deliberate that
exclusion can meaningfully deter it, and sufficiently culpable
that such deterrence is worth the price paid by the justice
system." Herring, 555 U.S. at 144; see also Davis, 564 U.S. at
240.
¶17 The "sole purpose" of the exclusionary rule "is to
deter future Fourth Amendment violations." Davis, 564 U.S. at
236-37. Therefore, exclusion is warranted only where there is
some present police misconduct, and where suppression will
appreciably deter that type of misconduct in the future. Id. at
237. The exclusionary rule applies only to police misconduct
that can be "most efficaciously" deterred by exclusion. Id.
(quoting United States v. Calandra, 414 U.S. 338, 348 (1974)).
9
No. 2019AP1404-CR
Specifically, "the exclusionary rule serves to deter deliberate,
reckless, or grossly negligent conduct, or in some circumstances
recurring or systemic negligence." Herring, 555 U.S. at 144.
"But when the police act with an objectively reasonable good-
faith belief that their conduct is lawful, or when their conduct
involves only simple, isolated negligence, the deterrence
rationale loses much of its force, and exclusion cannot pay its
way." Davis, 564 U.S. at 238 (cleaned up).
¶18 "Real deterrent value is a 'necessary condition for
exclusion,' but it is not 'a sufficient' one." Id. at 237
(quoting Hudson v. Michigan, 547 U.S. 586, 596 (2006)). In
Davis, the Court explained that the "analysis must also account
for the 'substantial social costs' generated by the rule." Id.
(quoting United States v. Leon, 468 U.S. 897, 907 (1984)). It
elaborated:
Exclusion exacts a heavy toll on both the judicial
system and society at large. It almost always
requires courts to ignore reliable, trustworthy
evidence bearing on guilt or innocence. And its
bottom-line effect, in many cases, is to suppress the
truth and set the criminal loose in the community
without punishment. Our cases hold that society must
swallow this bitter pill when necessary, but only as a
"last resort." For exclusion to be appropriate, the
deterrence benefits of suppression must outweigh its
heavy costs.
Id. (citations omitted).
¶19 Applying this rationale, the Supreme Court in Herring
held that a county's failure to update a computer database to
reflect the recall of an arrest warrant was only negligent, and
therefore was "not enough by itself to require 'the extreme
10
No. 2019AP1404-CR
sanction of exclusion.'" 555 U.S. at 140 (quoting Leon, 468
U.S. at 916). Similarly, in Davis, the Supreme Court refused to
exclude evidence that was obtained via a search conducted in
compliance with binding, but subsequently overruled, precedent.
564 U.S. at 232. Exclusion, it explained, was inappropriate
because it "would do nothing to deter police misconduct." Id.
¶20 We have followed suit as well. In Kerr, we explained
that no police misconduct occurred when an officer conducted an
arrest relying on dispatch's confirmation that the defendant had
a warrant out for his arrest. 383 Wis. 2d 306, ¶22. Exclusion
was improper because "the officers' conduct [was] at most
negligent, and isolated negligence is not 'misconduct' for
purposes of the exclusionary rule." Id. (citing Herring, 555
U.S. at 146-47).
¶21 Many more examples could be provided,5 but the
principle is clear: unless evidence was obtained by
sufficiently deliberate and sufficiently culpable police
misconduct, "[r]esort to the massive remedy of suppressing
5See, e.g., United States v. Leon, 468 U.S. 897, 916 (1984)
(reasonable reliance on a warrant later held invalid); Illinois
v. Krull, 480 U.S. 340, 342 (1987) (reasonable reliance on
subsequently invalidated statutes); Arizona v. Evans, 514
U.S. 1, 15-16 (1995) (reasonable reliance on arrest warrant
information in a database maintained by judicial employees);
State v. Ward, 2000 WI 3, ¶63, 231 Wis. 2d 723, 604 N.W.2d 517
(reasonable reliance on settled law subsequently overruled);
State v. Dearborn, 2010 WI 84, ¶44, 327 Wis. 2d 252, 786
N.W.2d 97 (refusing to exclude evidence where doing so "would
have absolutely no deterrent effect on officer misconduct").
11
No. 2019AP1404-CR
evidence of guilt is unjustified."6 Hudson, 547 U.S. at 599.
With these principles in mind, we turn to the facts at hand.
2. Application
¶22 In this case, the Sheriff's Office detectives acted by
the book. After a DNA sample from VanderHeyden's sock matched
Burch, officers checked the interdepartmental records already on
file with the police.7 They discovered the two-month-old Police
Department file documenting the investigation for the vehicle-
related incidents. In it, they found and reviewed Burch's
signed consent form and Officer Bourdelais' narrative further
documenting Burch's consent. The Sheriff's Office detectives
observed that neither the consent form nor the narrative listed
any limitations to the scope of consent. And the officers
reviewed the downloaded data, having every reason to think it
was lawfully obtained with Burch's unqualified consent.
¶23 Burch argues that the Sheriff's Office should have
obtained a warrant before accessing the Police Department's
6Failure to apply exclusion is usually described in our
cases as the "good faith" exception to the exclusionary rule.
See, e.g., Dearborn, 327 Wis. 2d 252, ¶4. However, the United
States Supreme Court has called the "good faith" label
confusing. Herring v. United States, 555 U.S. 135, 142 (2009).
The Supreme Court's most recent cases do not use that phrase as
a catchall for cases where exclusion is improper, and do not
describe their conclusion that exclusion was inappropriate as
applying a "good faith" exception. See id. at 147-48; Davis v.
United States, 564 U.S. 229, 249-50 (2011).
7Officers from both the Police Department and the Sheriff's
Office testified that it is common police practice for agencies
to share records with other agencies.
12
No. 2019AP1404-CR
data. But no case from this court or the federal courts has
suggested that accessing evidence previously obtained by a
sister law enforcement agency is a new search triggering a
renewed warrant requirement.8 Rather, the Sheriff's Office
detectives reasonably relied on Burch's signed consent form and
Officer Bourdelais' narrative to conclude that Burch consented
to the download of the data. They had no reason to think they
were engaging in illegal activity by reviewing interdepartmental
files and evidence. Far from it. Reliance on well-documented
computer records, like the detectives did here, is something the
Supreme Court has characterized as objectively reasonable police
conduct. Arizona v. Evans, 514 U.S. 1, 15-16 (1995). Thus,
there was no misconduct that would "render[] the evidence
suppressible under the exclusionary rule." Kerr, 383
Wis. 2d 306, ¶22.
¶24 Moreover, even if the Sheriff's Office's actions could
be labeled as some kind of misconduct, nothing they did would
rise beyond mere negligence. See id., ¶22 (concluding that "to
the extent that looking at a warrant before executing it may be
8 Justice Dallet's concurrence/dissent argues that courts
should treat cell phone data collected by law enforcement
differently than other types of evidence. It acknowledges that
the sharing of already-collected evidence without a warrant by
sister law enforcement agencies is routine and unproblematic,
but maintains a different kind of analysis should attend cell
phone evidence. We need not decide this question to conclude
exclusion is not warranted in this case. Justice Dallet's
approach would break new ground in Fourth Amendment
jurisprudence, and as such, the violation of her new proposed
rule does not implicate the kind of gross or systemic law
enforcement misconduct the exclusionary rule is meant to deter.
13
No. 2019AP1404-CR
best practice," failing to do so was "at most negligent");
Herring, 555 U.S. at 140 (holding that a county's failure to
update a computer database was negligent and therefore "not
enough by itself to require" exclusion). And mere negligence
does not warrant suppression. Id. at 144-45.
¶25 In addition, the societal cost of excluding the cell
phone data would far outweigh any deterrence benefit that
exclusion might provide. See Dearborn, 327 Wis. 2d 252, ¶35.
This is in part because there is nothing concerning under
current Fourth Amendment doctrine with how the Sheriff's Office
detectives conducted themselves. Even if the Police
Department's initial download or retention gave cause for
concern, it's not clear what behavior by the Sheriff's Office
Burch would have this court seek to deter.9 Based on the
arguments presented, Burch has given us no reason to deter law
enforcement reliance on the computer records of other law
enforcement agencies. In this case, the societal cost of
Many of Burch's arguments focus on the conduct of the
9
Police Department and the initial download of his cell phone
data. He argues that because the Police Department unlawfully
obtained the data, any subsequent accessing of the data violated
the Fourth Amendment because he retained a reasonable
expectation of privacy in it. But the conduct of the Police
Department has little bearing on whether we should apply the
exclusionary rule against the Sheriff's Office in this case.
The Police Department's involvement in this case was limited to
an investigation of unrelated crimes and was only fortuitously
useful to the Sheriff's Office's investigation of VanderHeyden's
homicide months later. Exclusion therefore would not serve as a
meaningful deterrent for the Police Department and is not
warranted on that basis.
14
No. 2019AP1404-CR
exclusion would far outweigh the limited benefit——if any——its
application could achieve.
¶26 We conclude that suppression of Burch's cell phone
data is not warranted under the exclusionary rule. Regardless
of whether a constitutional violation occurred, there was no
police misconduct to trigger application of the exclusionary
rule.
B. Fitbit Evidence
¶27 Burch also appeals the circuit court's denial of his
motion to exclude evidence associated with Detrie's Fitbit
device. Burch offers two arguments. First, he argues the
Fitbit evidence must be excluded because the State did not
produce expert testimony to establish its reliability. Second,
he maintains the Fitbit evidence was insufficiently
authenticated.10 We review these evidentiary rulings for an
erroneous exercise of discretion. State v. Nelis, 2007 WI 58,
¶26, 300 Wis. 2d 415, 733 N.W.2d 619.
10Burch also argues that admission of the Fitbit evidence
violates the Confrontation Clause of the Sixth Amendment to the
United States Constitution. Burch concedes, however, that his
novel argument "does not neatly fit within the test set forth in
Crawford v. Washington, 541 U.S. 36 (2004)," and that he raised
the issue solely "to preserve for review before higher courts."
Accordingly, we reject Burch's Confrontation Clause claim and do
not address it further.
15
No. 2019AP1404-CR
1. Expert Testimony
¶28 We have held that that "the requirement of expert
testimony is an extraordinary one" and should apply only "when
the issues before the jury are 'unusually complex or esoteric.'"
State v. Kandutsch, 2011 WI 78, ¶28, 336 Wis. 2d 478, 799
N.W.2d 865 (quoting another source). Before compelling expert
testimony, "the circuit court must first find that the
underlying issue is 'not within the realm of the ordinary
experience of mankind.'" Id. (quoting Cramer v. Theda Clark
Mem'l Hosp., 45 Wis. 2d 147, 150, 172 N.W.2d 427 (1969)). What
falls within the "ordinary experience of mankind," meanwhile,
turns on the circuit court's exercise of its discretion "on a
case-by-case basis" to decide whether "the issue is outside the
realm of lay comprehension" or within the "common knowledge" of
"the average juror." Id., ¶29.
¶29 Burch argues that the Fitbit evidence was improperly
admitted because the circuit court should have required expert
testimony to establish the reliability of the science underlying
Fitbit's technology. He notes that the Fitbit device features
"a three-axis accelerometer sensor that generates data
representing the user's movements," but explains that his
"greater concern is with how the device processes the data into
a meaningful output, how that output is exchanged with a phone
or computer, and how that evidence ultimately ended up in
Fitbit's business records."
¶30 In its written order rejecting Burch's argument that
expert testimony was required, the circuit court explained that
16
No. 2019AP1404-CR
Fitbit's step counters have been in the marketplace since 2009,
and the "principle idea behind pedometers . . . for a
significantly longer period than that." Many smartphones, the
court added, "come equipped with a pedometer by default."
Analogizing to a watch and a speedometer, the court noted that
even though the average juror may not know "the exact mechanics"
of a technology's "internal workings," the public may
nevertheless "generally understand[] the principle of how it
functions and accept[] its reliability." Similarly, the court
reasoned, a Fitbit's use of sophisticated hardware and software
does not render it an "unusually complex or esoteric" technology
because the average juror is nevertheless familiar with what a
Fitbit does and how it is operated.
¶31 This conclusion was reasonable and within the circuit
court's discretionary authority. The circuit court correctly
interpreted the standard for requiring expert testimony and
reasonably applied that standard to the Fitbit evidence before
it. Given the widespread availability of Fitbits and other
similar wireless step-counting devices in today's consumer
marketplace, the circuit court reasonably concluded Detrie's
Fitbit was not so "unusually complex or esoteric" that the jury
needed an expert to understand it.11 The circuit court's
To the extent Burch now argues that the Fitbit is outside
11
the realm of lay comprehension because it is an "internet of
things" device, we are unpersuaded. Wireless technology is
nothing new. It is entirely within the "ordinary experience of
mankind" to use a Bluetooth or Wi-Fi connection to transfer data
from one device to another.
17
No. 2019AP1404-CR
conclusion that expert testimony was not required under these
circumstances was within the circuit court's discretion.12
2. Authentication
¶32 Wisconsin Stat. § 909.01 (2019-20)13 sets out the
evidentiary standard for authentication: "The requirements of
authentication or identification as a condition precedent to
admissibility are satisfied by evidence sufficient to support a
finding that the matter in question is what its proponent
claims." Simply put, authentication requires that a circuit
court conclude, within its discretion, that the finder of fact
could reasonably determine that the evidence sought to be
admitted is what its proponent says it is. Id.; State v. Smith,
2005 WI 104, ¶¶31-33, 283 Wis. 2d 57, 699 N.W.2d 508. In this
case, that means the State's authentication obligation is to
present sufficient evidence to support a finding that the
records produced by the State are in fact Fitbit's records
associated with Detrie's Fitbit device.
¶33 Notably, Burch does not actually disagree that the
State's records are accurate copies of Fitbit's records
associated with Detrie's Fitbit device. Instead, he focuses his
challenge on whether the State properly authenticated "the
12Of course, opposing counsel may attack the reliability of
admitted evidence. T.A.T. v. R.E.B., 144 Wis. 2d 638, 652-53,
425 N.W.2d 404 (1988).
13All subsequent references to the Wisconsin Statutes are
to the 2019-20 version unless otherwise indicated.
18
No. 2019AP1404-CR
information within those records." Specifically, he argues that
"the State failed to show that the Fitbit device reliably and
accurately registered Detrie's steps that evening, and that that
data was reliably and accurately transmitted to Fitbit's
business records without manipulation."
¶34 Burch's argument reaches beyond the threshold question
authentication presents. The circuit court's authentication
obligation is simply to determine whether a fact-finder could
reasonably conclude evidence is what its proponent claims it to
be. Wis. Stat. § 909.01. The circuit court did so here by
reviewing the Fitbit records and the affidavit of "a duly
authorized custodian of Fitbit's records" averring that the
records "are true and correct copies of Fitbit's customer data
records," and then concluding the data was self-authenticating
under Wis. Stat. § 909.02(12).14 The circuit court's obligation
is not to scrutinize every line of data within a given record
and decide whether each line is an accurate representation of
the facts. Rather, once the circuit court concludes the fact-
finder could find that the records are what their proponent
claims them to be, the credibility and weight ascribed to those
More precisely, the circuit court held that the records
14
were self-authenticating as certified records of regularly
conducted activity. See Wis. Stat. § 909.02(12). Burch has
not, either before the circuit court or this court, challenged
the statements in the affidavit from Fitbit certifying that the
records it provided are accurate copies of its records
associated with Detrie's Fitbit device.
19
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records are questions left to the finder of fact.15 State v.
Roberson, 2019 WI 102, ¶25, 389 Wis. 2d 190, 935 N.W.2d 813.
The circuit court's conclusion that the Fitbit records were
sufficiently authenticated therefore was within its discretion.
III. CONCLUSION
¶35 Burch's appeal of his conviction for first-degree
intentional homicide challenged the denial of two pre-trial
evidentiary orders. We uphold both orders, and therefore affirm
the judgment of conviction. Burch's cell phone data was
properly admitted because, even if there was some constitutional
defect in how it was obtained or retained, exclusion would be an
improper remedy. The circuit court also permissibly exercised
its discretion in admitting the Fitbit evidence; no expert was
required and the State sufficiently authenticated the records
from Fitbit.
By the Court.——The judgment of the circuit court is
affirmed.
Here, too, opposing counsel can attack the reliability of
15
admitted evidence. See T.A.T., 144 Wis. 2d at 652-53.
20
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¶36 REBECCA GRASSL BRADLEY, J. (concurring). I join the
majority opinion in full. Because there are no controlling
cases interpreting the Fourth Amendment to prohibit the second
search of Burch's cellphone by the Brown County Sheriff's Office
(Sheriff's Office), the exclusionary rule does not apply and
suppression of the evidence obtained from that search would be
improper.1 I write separately to discuss the application of the
Fourth Amendment to warrantless second searches of smartphones
without consent.
¶37 Under the original meaning of the Fourth Amendment,
law enforcement generally will need a warrant to search the
contents of a smartphone, absent an exception to the warrant
requirement. The consent-to-search exception, which the State
argues authorized law enforcement to conduct a second search of
Burch's smartphone data, does not extend to a second search of a
smartphone by a different law enforcement agency investigating
an entirely separate crime. "Modern cell phones are not just
another technological convenience. With all they contain and
all they may reveal, they hold for many Americans 'the privacies
of life.'" Riley v. California, 573 U.S. 373, 403 (2014)
(quoting Boyd v. United States, 116 U.S. 616, 630 (1886)). The
Fourth Amendment secures "'the privacies of life' against
'arbitrary power,'" and embodies the "central aim of the
Framers . . . 'to place obstacles in the way of a too permeating
1I also agree with the majority that the circuit court did
not erroneously exercise its discretion by admitting evidence
from Douglass Detrie's Fitbit device.
1
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police surveillance.'" Carpenter v. United States, 138 S. Ct.
2206, 2214 (2018) (quoted sources omitted).
¶38 The contents of smartphones constitute "papers" and
"effects" secured by the Fourth Amendment, giving each of those
categories their historical meanings and bearing in mind that "a
cell phone search would typically expose to the government far
more than the most exhaustive search of a house." Riley, 573
U.S. at 396. Accordingly, law enforcement generally must get a
warrant before searching a cell phone. Id. at 403. Because
Burch's consent to search covered only the Green Bay Police
Department's initial search of his smartphone for evidence
related to a hit-and-run investigation, a warrant should have
been procured before the Sheriff's Office searched Burch's
smartphone data as part of an unrelated murder investigation.
Because neither this court nor the United States Supreme Court
has decided this novel issue, the Sheriff's Office committed no
misconduct in searching Burch's cell phone and the circuit court
properly admitted the evidence obtained from the search.
Accordingly, I respectfully concur.
I
¶39 In June 2016, a few weeks after Nicole VanderHeyden's
murder and the ensuing investigation by the Sheriff's Office,
the Green Bay Police Department (Police Department) began
investigating an entirely unrelated crime: an auto theft that
resulted in a hit-and-run incident.2 The stolen car belonged to
Burch's roommate, and law enforcement identified Burch as a
2 The vehicle was also lit on fire.
2
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person of interest because he had last driven the car. Officer
Robert Bourdelais of the Police Department interviewed Burch
about the hit and run. Burch denied any involvement, but
informed Officer Bourdelais that, on the night of the hit and
run, he was texting a woman who lived one block away from the
location of the accident. Burch stated that he did not go to
the woman's house on the night of the incident, and never made
arrangements to go to her house. According to Officer
Bourdelais' testimony, he and Burch had the following exchange:
I asked him if I could see the text messages between
him and [the woman], if my lieutenant and I could take
a look at his text messages. He said that we
could . . . . I [then] asked him if he would be
willing to let me take his phone to this detective,
download the information off the phone and then I'd
bring the phone right back to him, probably take a
half an hour and he said that would be fine.
¶40 The attorney eliciting Officer Bourdelais' testimony
inquired: "When you asked [Burch] about downloading the
information off of his phone, did you specifically limit the
information to the text messages when you were talking to him?"
Officer Bourdelais responded:
No, I didn't. Initially, when I had asked him, hey,
do you mind if we take a look at those text messages,
I refer to them as text messages because he said he
was texting [the woman] back and forth, but from my
experience as a police officer I know people
communicate [by] phone calls, text messages, texting
apps like WhatsApp, MINE, Facebook Messenger, things
like that. So that's the information, I wanted
information to corroborate that whatever conversation
he had with [the woman] or communication he had
supported his claims that he never went over to her
house or made arrangements to go over to her house.
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¶41 Following the exchange between Burch and Officer
Bourdelais, Burch signed a consent form which read as follows:
"I, George Stephen Burch, . . . voluntarily give Det. Danielski,
Officer Bourdelais, or any assisting personnel permission to
search my . . . Samsung cellphone." Subsequently, at the
instruction of Officer Bourdelais, a Police Department forensic
examiner downloaded all of the data from Burch's cellphone into
the Police Department records database. The forensic examiner
then converted the data into a readable format, and tabbed the
data into categories such as text messages, images, and internet
history. At the homicide trial, the forensic examiner testified
that the Police Department retains smartphone data for an
indefinite amount of time, noting that "[e]ver since [she] [has]
been employed with [the Police Department], [they] have saved
all extractions for long-term storage for as far back as [she]
[has] been employed," which was roughly two years at the time of
trial.
¶42 In August 2016 (two months after Burch consented to
the search of his phone for the hit-and-run investigation), the
Sheriff's Office identified Burch as a person of interest in the
investigation into the murder of VanderHeyden based upon a DNA
match on VanderHeyden's socks. Relying on databases shared
between the Sheriff's Office and other local entities,
detectives from the Sheriff's Office discovered that the Police
Department had prior contact with Burch while investigating the
unrelated hit-and-run incident. After the detectives learned
that the Police Department had extracted all of Burch's
4
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smartphone data in June 2016, they procured a copy of the data
from the Police Department and searched its contents "for
anything in the timeframe of the night of [the murder] into the
[following] morning, whether it be calls, texts, internet
history, any kind of location data available from that device."
The detectives did not obtain a warrant for this search. In
reviewing the data, the detectives discovered that, shortly
after the murder, Burch repeatedly searched for news articles
about the murder using his internet browser.
¶43 Additionally, during their warrantless search of the
smartphone's contents, the detectives learned that Burch had a
Google email account (Gmail). The detectives were aware that
Gmail addresses are associated with a Google Dashboard, which
tracks an individual's location based upon GPS, Wi-Fi, and
cellphone tower data. The detectives procured a search warrant
to obtain Google Dashboard information from Google. The
location data placed Burch's smartphone at various critical
places on the night of the murder, including the location of
VanderHeyden's body and the on-ramp where her discarded clothing
was discovered.
¶44 Burch was arrested and charged with first-degree
intentional homicide. In a pre-trial motion, Burch moved to
suppress the evidence obtained by the Sheriff's Office from the
warrantless search of his smartphone data.3 Burch argued that
the Sheriff's Office "violated the Fourth Amendment when [it]
Burch also filed a motion to exclude evidence related to
3
Detrie's Fitbit device, which the circuit court denied.
5
No. 2019AP1404-CR.rgb
searched the phone data initially seized by [the Police
Department]." Specifically, Burch contended that the Sheriff's
Office "blew past Mr. Burch's scope of consent, and likewise,
obliterated any Fourth Amendment warrant exceptions." The
circuit court denied Burch's suppression motion, and the State
introduced at trial the evidence obtained from the smartphone.
The jury convicted Burch of first-degree intentional homicide.
Burch appealed the circuit court's decision to admit the
evidence procured by the Sheriff's Office from its search of his
smartphone data. The court of appeals certified Burch's Fourth
Amendment challenge to this court, and we accepted
certification.
II
¶45 The Fourth Amendment provides:
The right of the people to be secure in their persons,
houses, papers, and effects, against unreasonable
searches and seizures, shall not be violated, and no
Warrants shall issue, but upon probable cause,
supported by Oath or affirmation, and particularly
describing the place to be searched, and the persons
or things to be seized.
U.S. Const. amend. IV. "The first clause outlaws promiscuous
search and seizure, even as the second clarifies precisely what
will be required for a particularized warrant to be valid."
Laura K. Donohue, The Original Fourth Amendment, 83 U. Chi. L.
Rev. 1181, 1193 (2016); State v. Pinder, 2018 WI 106, ¶¶48-51,
384 Wis. 2d 416, 919 N.W.2d 568. As understood at the time the
Fourth Amendment was ratified, "[t]he government could not
violate the right against search and seizure of one's person,
house, papers, or effects absent either a felony arrest or a
6
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warrant meeting the requirements detailed in the second clause."
Donohue, supra, at 1193.
¶46 As the United States Supreme Court has repeatedly
held, "the ultimate touchstone of the Fourth Amendment is
'reasonableness.'" Brigham City v. Stuart, 547 U.S. 398, 403
(2006). "[W]hether an individual has a reasonable expectation
of privacy in avoiding the method of search and
a reasonable expectation of privacy in the place searched are
the questions that drive a court's examination of the
reasonableness of the search." State v. Brereton, 2013 WI 17,
¶32, 345 Wis. 2d 563, 826 N.W.2d 369. "The general rule is that
searches and seizures conducted without a warrant are not
reasonable." State v. Randall, 2019 WI 80, ¶10, 387
Wis. 2d 744, 930 N.W.2d 223. However, there are a number of
exceptions to the warrant requirement. See Riley, 573 U.S. at
382 ("In the absence of a warrant, a search is reasonable only
if it falls within a specific exception to the warrant
requirement."). "One of the exceptions to the warrant rule is
that an individual's consent to search satisfies the
constitutional 'reasonableness' requirement." Randall, 387
Wis. 2d 744, ¶10; see also Birchfield v. North Dakota, 136 S.
Ct. 2160, 2185 (2016) ("It is well established that a search is
reasonable when the subject consents[.]"). "If a search is
premised on an individual's consent, it must cease immediately
upon revocation of that consent," and an individual "may of
course delimit as she chooses the scope of the search to which
7
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she consents." Randall, 387 Wis. 2d 744, ¶10 (internal
alterations and citations omitted).
¶47 Just a few years ago, the United States Supreme Court
addressed the Fourth Amendment's application to a modern
phenomenon: the proliferation of smartphones and their ever-
increasing capacity to store mass amounts of data. The Court
held that law enforcement generally must obtain a warrant before
conducting a search of smartphone data. Specifically, the Riley
Court clarified that "[its] holding . . . is not that the
information on a cell phone is immune from search," but "instead
that a warrant is generally required before such a search, even
when a cell phone is seized incident to arrest."4 Riley, 573
U.S. at 401. In reaching this holding, the Court recognized the
"pervasiveness that characterizes cell phones" and how "[c]ell
phones differ in both a quantitative and a qualitative sense
from other objects." Id. at 393, 395. "The possible intrusion
on privacy is not physically limited in the same way [as other
objects] when it comes to cell phones." Id. at 394. "An
internet search and browsing history, for example, can be found
on an internet-enabled phone and could reveal an individual's
private interests or concerns," and "historic location
4Although Riley involved the search-incident-to-arrest
exception to the Fourth Amendment warrant requirement, the
principles it espouses apply more broadly. See Riley v.
California, 573 U.S. 373, 386 (2014) ("[O]fficers must generally
secure a warrant before conducting such a search [of a cell
phone]."); see also People v. Hughes, 958 N.W.2d 98, 108 (Mich.
2020) ("In Riley v. California, the Supreme Court of the United
States held that officers must generally obtain a warrant before
conducting a search of cell-phone data.").
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information" could allow law enforcement to "reconstruct
someone's specific movements down to the minute." Id. at 395-
96.
¶48 The United States Supreme Court fully understood that
its decision "[would] have an impact on the ability of law
enforcement to combat crime." Id. at 401. After all, "[c]ell
phones have become important tools in facilitating coordination
and communication" for individuals committing crimes and "can
provide valuable incriminating information about dangerous
criminals." Id. But "[p]rivacy comes at a cost." Id. And the
Fourth Amendment is designed to safeguard the people's security
against unreasonable government intrusion. Riley recognizes
that the Fourth Amendment safeguards this right by generally
requiring law enforcement to procure a warrant before searching
a smartphone.
¶49 A warrant requirement for searches of smartphone data
comports with the original meaning of the Fourth Amendment. The
Framers, "after consulting the lessons of history, designed our
Constitution to place obstacles in the way of a too permeating
police surveillance, which they seemed to think was a greater
danger to a free people than the escape of some criminals from
punishment." United States v. Di Re, 332 U.S. 581, 595 (1948).
In particular, "the Fourth Amendment was the founding
generation's response to the reviled 'general warrants' and
'writs of assistance' of the colonial era, which allowed British
officers to rummage through homes in an unrestrained search for
evidence of criminal activity. Opposition to such searches was
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in fact one of the driving forces behind the Revolution itself."
Riley, 573 U.S. at 403. "Indeed, the character of that threat
implicates the central concern underlying the Fourth Amendment——
the concern about giving police officers unbridled discretion to
rummage at will among a person's private effects." Arizona v.
Gant, 556 U.S. 332, 345 (2009). For the Framers, it was
absolutely necessary to ensure "the government not be allowed
free rein to search for potential evidence of criminal
wrongdoing." Donohue, supra, at 1194.
¶50 The Framers designed the Fourth Amendment to protect
the people from government overreach. Described as the "very
essence of constitutional liberty and security," the Fourth
Amendment applies to "all invasions on the part of the
government and its employes of the sanctity of a man's home and
the privacies of life." Boyd, 116 U.S. at 630. "It is not the
breaking of [one's] doors, and the rummaging of his drawers,
that constitutes the . . . offense; but it is the invasion of
his infeasible right of personal security, personal liberty, and
private property[.]" Id. With this understanding in mind,
"[t]he Supreme Court has . . . confirmed that the basic purpose
of the Fourth Amendment 'is to safeguard the privacy and
security of individuals against arbitrary invasions by
governmental officials'"——that is, "to secure 'the privacies of
life' against 'arbitrary power.'" Matthew DeVoy Jones, Cell
Phones are Orwell's Telescreen: The Need for Fourth Amendment
Protection in Real-Time Cell Phone Location Information, 67
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Clev. St. L. Rev. 523, 533 (2019) (quoting Carpenter, 138 S. Ct.
at 2213-14).
¶51 The Fourth Amendment specifically recognizes the right
of people to be secure in their "persons, houses, papers, and
effects." U.S. Const. amend. IV; see United States v. Jones,
565 U.S. 400, 406 (2012) ("[F]or most of our history the Fourth
Amendment was understood to embody a particular concern for
government trespass upon the areas ('persons, house, papers, and
effects') it enumerates."). Much modern analysis of the Fourth
Amendment has centered upon the primacy of protecting "houses."
See Payton v. New York, 445 U.S. 573, 589 (1980) ("The Fourth
Amendment protects the individual's privacy in a variety of
settings. In none is the zone of privacy more clearly defined
than when bounded by the unambiguous physical dimensions of an
individual's home[.]"). However, as the Riley Court explained,
smartphones implicate privacy interests more compelling than
even those associated with the home. "A cell phone search would
typically expose to the government far more than the most
exhaustive search of a house: A phone not only contains in
digital form many sensitive records previously found in the
home; it also contains a broad array of private information
never found in a home in any form[.]" Riley, 573 U.S. at 396-
97.
¶52 Given the nature of its contents, a smartphone is not
just another personal item; it is a device that holds many
modern "privacies of life"——an area that receives acute and
particularized protection from government interference under the
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Fourth Amendment. See Boyd, 116 U.S. at 630. Governmental
searches of smartphones invade "the indefeasible right of
personal security, personal liberty, and private property,"
which Americans hold "sacred." Id. Permitting law enforcement
to rummage through the data residing in smartphones without a
warrant would "allow[] free rein to search for potential
evidence of criminal wrongdoing," which the Fourth Amendment
prohibits. With respect to smartphone data, as in the home,
"all details are intimate details, because the entire area is
held safe from prying government eyes." See Kyllo v. United
States, 533 U.S. 27, 37 (2001).
¶53 The Fourth Amendment includes both "papers" and
"effects" among the four enumerated categories protected from
unreasonable searches. The contents of smartphones constitute
"papers" within the original understanding of the Fourth
Amendment. "Historically, private papers, including documents
and pamphlets that challenged governmental power, served as a
central point of contestation in the Founding era." Andrew
Guthrie Ferguson, The "Smart" Fourth Amendment, 102 Cornell L.
Rev. 547, 595-96 (2017). The Fourth Amendment's protection of
"papers" "reflect[s] the importance of freedom of thought,
expression, and communication." Id. According to Lord Camden
in his seminal decision in Entick v. Carrington, "papers are
often the dearest property a man can have." 19 How. St. Tr.
1029 (C.P. 1765).
¶54 The Framers' inclusion of "papers" within the
protections of the Fourth Amendment was motivated in part by the
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case of John Wilkes, "who was targeted for writing mocking
articles about King George III" and had his papers seized by
investigating officers. Ferguson, supra, at 596 (citation
omitted). "The Wilkes controversy . . . directly influenced the
[F]ramers of the Fourth Amendment. The English search and
seizure cases received extensive publicity in England and in
America, and the Wilkes case was the subject of as much
notoriety and comment in the colonies as it was in Britain."
Eric Schnapper, Unreasonable Searches and Seizures of Papers, 71
Va. L. Rev. 869, 912-13 (1985). "Wilkes' cause generated many
supporters among American colonists, some of whom became key
figures in the framing of the Constitution." Id. at 913. Based
upon Wilkes' case, "[p]rotecting private papers . . . became a
central rallying cry in the creation of constitutional liberty,"
receiving explicit protection under the United States
Constitution. Ferguson, supra, at 596.
¶55 Today, the people's "papers" largely exist in digital
form. "E-mails, texts, and other social media communication
have replaced letter writing." Id. at 599. Additionally,
calendars, notes, health information, photographs, restaurant
and hotel reservations, airline flights, shopping and browsing
histories, as well as banking transactions all reside in (or are
accessible from) smartphones, forming a digital diary of one's
life, accessible from a single source. Given the breadth and
detail of this information, "individuals have expectations of
privacy in their digital papers." Id. at 600. From the
Framers' outrage over the search of Wilkes' papers to the
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Court's concern regarding the search of David Riley's
smartphone, the overarching aim "has always been the protection
of ideas embodied in those papers"——not whether the papers are
in physical or digital form. Id. at 613.
¶56 Some portion of the contents of smartphones, as well
as the devices themselves, also constitute "effects," which
"have historically been understood to mean personal property——
the objects we possess." Id. at 578 (citing Dictionarium
Brittanicum (Nathan Baily ed., 1730) (defining "effects" as "the
goods of a merchant, tradesman") and Noah Webster, First Edition
of an American Dictionary of the English Language (1828)
(defining "effects" as "goods; moveables; personal estate")).
"The early American understanding distinguished personal
property from real property," and "personal property meant
physical belongings"——items which were "obviously prized by the
Founders" and accordingly received Fourth Amendment protection.
Id. Founding-era history "demonstrates that effects were
specifically included in the constitutional text [not only]
because of the harms to privacy and dignity that could be
incurred in their inspection, but also because of the risk of
mishandling or damage generally associated with interferences
with personal property." Maureen E. Brady, The Lost "Effects"
of the Fourth Amendment: Giving Personal Property Due
Protection, 125 Yale L.J. 946, 987 (2016). Founding-era sources
suggest the Framers understood "[p]ersonal property [to] give[]
its owner a right to exclude others from possessing, using, and
interfering with the effect"——and most of all to "protect[]
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privacy interests with respect to the property." Id. at 993-94
(discussing founding-era sources, including William Blackstone's
Commentaries and Lord Camden's judgment in Entick v.
Carrington).
¶57 Although "'effects' has captured rather less of the
[United States] Supreme Court's attention" than "papers" and
"houses," when the Court has addressed the topic, "property
considerations loom large." Laura K. Donohue, The Fourth
Amendment in a Digital World, 71 N.Y.U. Ann. Surv. Am. L. 553,
679 (2017). For example, in United States v. Jones, the United
States Supreme Court held that law enforcement's installation of
a GPS device on an individual's vehicle to monitor the vehicle's
movements constituted a "search" under the Fourth Amendment,
deeming it "beyond dispute" that a vehicle is an "effect" within
the meaning of the Fourth Amendment. 565 U.S. 400, 404 (2012).
The Court emphasized the government's "physical intrusion" of
the "effect" at issue. Id. at 411. The Court did not focus on
the physical attachment of the GPS device to the effect but
rather the device's capture of sensitive and private
information, "relay[ing] more than 2,000 pages of data over [a]
4-week period." Id. at 403; see also Ferguson, supra, at 606
("[In Jones] the real harm was exposing the revealing personal
data about the effect (car)."). That is, in Jones the Fourth
Amendment analysis turned on the "capturing of data trails" of
the owner and "invad[ing] the informational security of the
effect." Ferguson, supra, at 606. The Court's reasoning in
Jones applies no less to smartphones and the data they hold,
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supporting the characterization of smartphones as "effects"
entitled to constitutional protection from unreasonable searches
and seizures.
III
¶58 Having established a historical basis for the
application of the Fourth Amendment's warrant requirement to
smartphones and their data, it is necessary to address the
application of the consent exception to the warrant requirement
within the context of the facts of Burch's case. It is well-
established that "[o]ne of the exceptions to the warrant rule is
that an individual's consent to search satisfies the
constitutional 'reasonableness' requirement." Randall, 387
Wis. 2d 744, ¶10; see also Birchfield, 136 S. Ct. at 2185.
Burch gave consent for the Police Department to download and
search his smartphone and its data as part of the investigation
of the hit-and-run incident in June 2016. According to his
testimony, Officer Bourdelais asked Burch if "[he] could see the
text messages between him and [the woman]" on the night of the
hit-and-run incident. Officer Bourdelais then asked Burch if he
could "take his phone to this detective, download the
information off the phone" and then bring it right back to
Burch. Burch agreed to all requests in this exchange and signed
a consent form saying he "voluntarily give[s] Det. Danielski,
Officer Bourdelais, or any assisting personnel permission to
search [his] . . . Samsung cellphone." Burch permitted Officer
Bourdelais "or any assisting personnel" to download his
smartphone's data and search for evidence of the hit-and-run
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incident. Burch's consent encompassed the Police Department's
investigation of a particular crime. The Constitution permitted
this search. Schneckloth v. Bustamonte, 412 U.S. 218, 222
(1973) ("[A] search conducted pursuant to a valid consent is
constitutionally permissible.").
¶59 Two months later, a different law enforcement agency——
the Sheriff's Office——searched Burch's smartphone data while
investigating an entirely separate crime. This search went
beyond the scope of Burch's consent. Officer Bourdelais
questioned Burch in June 2016 regarding the hit-and-run incident
only, and obtained Burch's consent to download Burch's
smartphone data "[to] corroborate that whatever conversation
[Burch] had with [the woman] . . . supported his claims that he
never went over to her house" the night of the hit and run. The
consent form did not include any language authorizing a second
search by a separate law enforcement agency for a different
crime. The form authorized only Officer Bourdelais, the
forensic examiner (Det. Danielski), and their assisting
personnel to view the smartphone's contents. Any search beyond
the scope of Burch's consent would require a warrant.
¶60 The State argues that this court's decision in State
v. Betterley, 191 Wis. 2d 406, 529 N.W.2d 216 (1995), allows law
enforcement to take a "second look" at smartphone data that was
previously searched. That case does not apply to searches of
cell phone data. In Betterley, officers at the St. Croix County
Jail seized a ring from the defendant during an inventory
search. Id. at 414. Later that day, a New Richmond police
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officer asked to see the ring, believing it was evidence that
the defendant had committed insurance fraud. Id. at 415. The
New Richmond police officer retained the ring as evidence
without obtaining a warrant. Id. This court held that "the
permissible extent of the second look [at evidence] is defined
by what the police could have lawfully done without violating
the defendant's reasonable expectations of privacy during the
first search, even if they did not do it at that time." Id. at
418. Because the defendant had a diminished expectation in
privacy in the ring after forfeiting it during the first search,
the second look at the ring was permissible, so long as it was
"no more intrusive" than the first search. Id.
¶61 Betterley does not apply to cell phone data retrieved
pursuant to the owner's consent. Betterley involved an
inventory search of an item, not the consent-to-search exception
to the warrant requirement. Unlike searches conducted with
consent, inventory searches are "administrative by nature, not
an investigation motivated by a search for evidence." State v.
Weber, 163 Wis. 2d 116, 132, 471 N.W.2d 187 (1991). More
importantly, physical items such as rings are qualitatively
different than searches of smartphone data. Examination of a
ring reveals nothing more than the physically observable item
itself, while smartphones contain——and conceal——the "privacies
of life," which generally are not viewable by others at a
glance. For this reason, smartphones "differ in both a
quantitative and a qualitative sense from other objects."
Riley, 573 U.S. at 393. "[I]t is no exaggeration to say that
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many of the more than 90% of American adults who own a cell
phone keep on their person a digital record of nearly every
aspect of their lives——from the mundane to the intimate.
Allowing the police to scrutinize such records on a routine
basis is quite different from allowing them to search a personal
item or two in the occasional case." Id. at 395. Certainly,
"the possible intrusion on privacy is not physically limited in
the same way [as other objects] when it comes to cell phones."
Id. at 394. Accordingly, Betterley does not inform the Fourth
Amendment analysis governing searches of cell phone data.
¶62 Even if "a Fourth Amendment violation has occurred,"
however, it "does not mean the exclusionary rule applies,"
particularly because "exclusion [of evidence] is the last
resort." State v. Dearborn, 2010 WI 84, ¶35, 327 Wis. 2d 252,
786 N.W.2d 97. "To trigger the exclusionary rule, police
misconduct must be sufficiently deliberate that exclusion can
meaningfully deter it, and sufficiently culpable that such
deterrence is worth the price paid by the justice system." Id.,
¶36 (quoted source omitted). For the reasons stated in the
majority opinion, there was no misconduct by the Sheriff's
Office. Neither this court nor the United States Supreme Court
has declared that second searches of cell phone data by separate
law enforcement agencies require a warrant. Accordingly,
suppression of the evidence obtained during the Sheriff's
Office's second search would be inappropriate and I respectfully
concur.
19
No. 2019AP1404-CR.rgb
* * *
¶63 "The great end, for which men entered into society,
was to secure their property." Entick v. Carrington, 19 How.
St. Tr. 1029 (C.P. 1765) (Lord Camden presiding). "Property
must be secured, or liberty cannot exist." Discourses on
Davila, in 6 The Works of John Adams 280 (C. Adams ed. 1851).
"The Fourth Amendment imposes limits on search-and-seizure
powers in order to prevent arbitrary and oppressive interference
by enforcement officials with the privacy and personal security
of individuals." United States v. Martinez-Fuerte, 428 U.S.
543, 554 (1976). Because smartphones contain the "privacies of
life," law enforcement generally needs a warrant to search the
data they hold unless an exception to the warrant requirement
applies.
20
No. 2019AP1404-CR.rfd
¶64 REBECCA FRANK DALLET, J. (concurring in part,
dissenting in part). Under the Fourth Amendment, when the
police want to search a person's private information, they
generally need a warrant. The Brown County Sheriff's Office
searched George Steven Burch's private cell phone data without
obtaining a warrant, assuming that Burch's consent for another
agency to download his phone's data for a wholly separate
investigation obviated its Fourth Amendment duty to do so. It
did not. The Sheriff's Office's warrantless search of Burch's
cell phone data violated the Fourth Amendment, and the evidence
obtained from that unlawful search should be suppressed. The
majority opinion's contrary holding ignores the novel
constitutional problems presented by private cell phone
information, is inconsistent with the Fourth Amendment's text,
and undermines the exclusionary remedy for Fourth Amendment
violations. I therefore respectfully dissent from that part of
the majority opinion.1
I. BACKGROUND
¶65 A Green Bay Police Department (GBPD) officer
interviewed Burch while investigating crimes involving the car
Burch would borrow for work. Burch denied his involvement but
acknowledged that he was text messaging a friend that night who
lived near the scene. When the officer asked Burch if he and
his lieutenant could see those text messages, Burch verbally
consented. After the officer explained that it was easier to
1I join Parts I. and II.B. of the majority opinion because
I agree that the circuit court permissibly admitted evidence
regarding a Fitbit device.
1
No. 2019AP1404-CR.rfd
download "the information" from the phone than to take
screenshots, Burch verbally consented to allowing the officer to
take his phone to a GBPD detective for that purpose.2 The
officer then presented Burch with a standardized written consent
form. The form contained the heading "City of Green Bay Police
Department" and indicated that Burch "voluntarily" gave a named
GBPD officer, a named GBPD detective, as well as any "assisting
personnel," "permission to search" his "Samsung Cellphone."
Burch signed the form. The officer testified that he requested
only "text messages, phone calls, Facebook posts, and
photographs taken any time after 11:00 p.m." the night of the
accident; yet, to access that information, the GBPD downloaded
the entire contents of Burch's phone.
¶66 Two months later, the Sheriff's Office was
investigating a homicide that had occurred a few weeks before
the crimes being investigated by the GBPD. It matched Burch's
DNA to DNA collected from the victim's body, her socks, and a
cord believed to be used in her murder. The Sheriff's Office
At trial, the officer testified that by "the information,"
2
he meant any communications between Burch and his friend that
would corroborate Burch's alibi:
Initially, when I had asked [Burch], hey, do you mind
if we take a look at those text messages, I refer to
them as text messages because he said he was texting
[his friend] back and forth, but from my experience as
a police officer I know people communicate phone
calls, text messages, texting apps like WhatsApp,
MINE, Facebook Messenger, things like that. So that's
the information, I wanted information to corroborate
that whatever conversation he had with [his friend] or
communication he had supported his claims that he
never went over to [the victim's] house or made
arrangements to go over to her house.
2
No. 2019AP1404-CR.rfd
also discovered that the GBPD had retained the full data
extraction from Burch's cell phone. After reviewing the GBPD's
files and seeing Burch's signed consent form, the Sheriff's
Office searched that data without first obtaining a warrant.
The search led the Sheriff's Office to Burch's internet search
history and his Google email account. The internet history
revealed that Burch had viewed online stories about the victim's
disappearance 64 times. The email account allowed the Sheriff's
Office to issue Google a subpoena for Burch's Google Dashboard
records, which included his location data from the night of the
murder. The location data placed Burch's cell phone near the
victim's residence and the field where her body was discovered
around the time of the victim's death.
II. ANALYSIS
¶67 The Fourth Amendment inquiry here is two-fold. The
first consideration is whether the Sheriff's Office's
warrantless search of the GBPD's download of Burch's data was
unreasonable. If so, it violated the Fourth Amendment, and the
question becomes whether excluding the unlawfully obtained
evidence would sufficiently deter the same police conduct in the
future. These questions involve a mixed standard of review,
under which we uphold the circuit court's findings of historical
fact unless they are clearly erroneous, but we review de novo
the application of constitutional principles to those facts.
See State v. Blackman, 2017 WI 77, ¶25, 377 Wis. 2d 339, 898
N.W.2d 774.
3
No. 2019AP1404-CR.rfd
A. The Sheriff's Office's Warrantless Search Was Unreasonable.
¶68 The Fourth Amendment to the United States Constitution
prohibits the government from conducting "unreasonable" searches
of a person, a person's home, or her "effects":
The right of the people to be secure in their persons,
houses, papers, and effects, against unreasonable
searches and seizures, shall not be violated, and no
warrants shall issue, but upon probable cause . . . .
The Amendment seeks to secure "the privacies of life" against
such unreasonable searches by placing "obstacles in the way of a
too permeating police surveillance." See Carpenter v. United
States, 585 U.S. ___, 138 S. Ct. 2206, 2214 (2018). Police
surveillance amounts to a "search," for purposes of the Fourth
Amendment, when it collects information in which the person has
a reasonable expectation of privacy. E.g., id. at 2213-14.
¶69 To protect one's reasonable expectation of privacy,
the text of the Fourth Amendment communicates a "strong
preference for searches conducted pursuant to a warrant." See
Illinois v. Gates, 462 U.S. 213, 236 (1983); U.S. Const.
amnd. IV. Indeed, a warrantless search is per se unreasonable,
see Schneckloth v. Bustamonte, 412 U.S. 218, 219 (1973), and
presumptively violates the Fourth Amendment, see State v.
Tate, 2014 WI 89, ¶27, 357 Wis. 2d 172, 849 N.W.2d 798. That
presumption is overcome only when the warrantless search falls
under one of the "few specifically established and well-
delineated exceptions." State v. Coffee, 2020 WI 53, ¶24, 391
Wis. 2d 831, 943 N.W.2d 845.
¶70 Consent is one such exception. State v. Hogan, 2015
WI 76, ¶55, 364 Wis. 2d 167, 868 N.W.2d 124. As with any
4
No. 2019AP1404-CR.rfd
exception to the warrant requirement, consent is "jealously and
carefully drawn," and must be "confined in scope" and "strictly
circumscribed." See Jones v. United States, 357 U.S. 493, 499
(1958); Terry v. Ohio, 392 U.S. 1, 25-26, 29 (1968). Consent to
a particular search must therefore be "unequivocal and
specific." State v. Reed, 2018 WI 109, ¶8, 384 Wis. 2d 469, 920
N.W.2d 56. Even absent express limits, the scope of consent is
neither "boundless" nor "perpetual." See State v. Douglas, 123
Wis. 2d 13, 21-22, 365 N.W.2d 580 (1985) (lead opinion).
Rather, its scope is determined objectively as "the typical
reasonable person [would] have understood" it from "the exchange
between the officer and the suspect." Florida v. Jimeno, 500
U.S. 248, 251 (1991). When the police rely on consent as their
justification for not getting a warrant, the State carries the
burden to demonstrate by clear and convincing evidence that the
search remained within the scope of that consent. See Reed, 384
Wis. 2d 469, ¶58; Douglas, 123 Wis. 2d at 22 (explaining that a
warrantless search exceeding the scope of consent is
unreasonable).
¶71 The lawfulness of the Sheriff's Office's search
therefore turns on two sub-questions: (1) although he consented
to specific GBPD personnel downloading his cell phone
information, did Burch maintain a reasonable expectation of
privacy in that information such that the Sheriff's Office
review of it was a Fourth Amendment search; and, if so, (2) did
the Sheriff's Office act unreasonably by searching the GBPD's
download of Burch's cell phone data without a warrant, in light
of Burch's consent to the GBPD?
5
No. 2019AP1404-CR.rfd
1. Burch Maintained a Reasonable Expectation of Privacy in the
GBPD's Download of His Cell Phone Data.
¶72 In the Fourth Amendment context, the United States
Supreme Court has clearly expressed that cell phone data is in
an evidence class of its own because it "implicate[s] privacy
concerns far beyond those implicated by the search of" other
physical belongings. Riley v. California, 573 U.S. 373, 393
(2014). Cell phones are unique in that they are almost always
with us and they store "vast quantities of personal
information." Id. at 386. Thus, by carrying cell phones,
people carry with them "a digital record of nearly every aspect
of their lives——from the mundane to the intimate." Id. at 395.
That digital record may include a person's internet "search and
browsing history" and "[h]istoric location information," see id.
at 395-96, allowing someone with access to that information to
"generate[] a precise, comprehensive record of a person's public
movements that reflects a wealth of detail about her familial,
political, professional, religious, and sexual associations,"
see United States v. Jones, 565 U.S. 400, 415 (2012)
(Sotomayor, J., concurring). Although traditionally most
private information was kept in one's home, advances in digital
technology have shifted that paradigm such that searching a
personal cell phone "would typically expose to the government
far more than the most exhaustive search of a house."
Riley, 573 U.S. at 396-97. Accordingly, people have a unique
and heightened expectation of privacy in their cell phone data
that demands commensurate Fourth Amendment protection. See id.
at 386, 393; People v. Hughes, 958 N.W.2d 98, 112 (Mich. 2020)
6
No. 2019AP1404-CR.rfd
("Riley distinguished cell-phone data from other items . . . in
terms of the privacy interests at stake.").
¶73 The unique privacy expectation in cell phone data
informs why Burch's consent to the GBPD does not relieve the
Sheriff's Office of its obligation to get a warrant for its own
review. Burch's consent, as "the typical reasonable person
[would] have understood" it, had the "expressed object" of the
GBPD reviewing messages to verify his alibi for the GBPD's
investigation. See Jimeno, 500 U.S. at 251. The GBPD officer's
report explained that Burch "consented to Lt. Allen and I [two
GBPD officers] looking at the text messages between him and
[Burch's acquaintance] last night and also indicated I could
take his phone to the department to have the information on it
downloaded." Burch's signed consent form is also specific to
the "City of Green Bay Police Department" and indicated that
Burch gave certain members of the GBPD permission to search his
phone. Critically absent from the report or the consent form is
any mention of any other law enforcement agency, the possibility
of the GBPD sharing the entirety of the downloaded data, or even
that Burch was consenting to the GBPD retaining indefinitely all
of his phone's information. Cf. Douglas, 123 Wis. 2d at 21-22.
7
No. 2019AP1404-CR.rfd
¶74 Burch's consent was therefore limited to the GBPD for
the GBPD's investigation.3 See Terry, 392 U.S. at 25-26, 29
(requiring courts to interpret warrant exceptions as "confined
in scope" and "strictly circumscribed"). With respect to other
agencies and their investigations, Burch maintained a reasonable
expectation of privacy in the data downloaded by the GBPD but
unrelated to its investigation, including his internet search
history and Google email account. See Carpenter, 138 S. Ct.
at 2217 (holding that, because of cell phone data's "unique
nature," a person "maintains a legitimate expectation of
privacy" in the data even after consensually giving it to
another party for a limited purpose); Hughes, 958 N.W.2d at 111
(concluding that the lawful seizure and search of certain cell
phone information does not "extinguish[] that otherwise
reasonable expectation of privacy in the entirety" of that
information). Consequently, the Sheriff's Office's subsequent
review of Burch's data invaded Burch's reasonable expectation of
privacy such that it was a search under the Fourth Amendment.
2. The Sheriff's Office Acted Unreasonably in Searching the
GBPD's Download of Burch's Cell Phone Data.
¶75 The Sheriff's Office decided that no warrant was
required for its search after determining that Burch's consent
The circuit court's determination that Burch placed no
3
parameters on the scope of his consent is suspect given that his
conversation with the GBPD about his phone was strictly limited
to his text messages. The categorical uniqueness of private
cell phone data requires circuit courts to take seriously the
admonition that exceptions to the warrant requirement like
consent be interpreted as "confined in scope" and "strictly
circumscribed." See Riley v. California, 573 U.S. 373, 382, 393
(2014); Terry v. Ohio, 392 U.S. 1, 25-26, 29 (1968).
8
No. 2019AP1404-CR.rfd
to the GBPD extended to the Sheriff's Office. But as discussed
above, Burch's "unequivocal and specific" consent extended only
to certain members of the GBPD, and only so they could review
his text messages to confirm his alibi. See Reed, 384
Wis. 2d 469, ¶8. Burch did not consent to all of the
information on his phone being available to other law
enforcement agencies for some later, unrelated investigation.
And the Sheriff's Office did not independently get Burch's
consent to search his cell phone information.
¶76 Given those facts, no reasonable person in Burch's
position would have understood that his consent to the GBPD was
an open invitation for any other law enforcement agency to
search his private information whenever it wanted to and without
a warrant. Therefore, the consent exception to the Fourth
Amendment's warrant requirement does not apply to the Sheriff's
Office's subsequent warrantless search of Burch's private cell
phone data for an unrelated investigation. That search was
unreasonable and violated the Fourth Amendment.
B. Evidence of Burch's Google Location Data and His Internet
Search History Should Be Suppressed.
¶77 Having concluded that the Sheriff's Office's search
violated the Fourth Amendment, the next question is whether the
exclusionary rule applies; that is, whether excluding, or
suppressing, the unlawfully obtained evidence would sufficiently
deter the same police conduct in the future. Here, Burch's
Google location data and his internet search history should be
excluded because if they are not, other law enforcement agencies
are likely to repeat the Sheriff's Office's unconstitutional
9
No. 2019AP1404-CR.rfd
search of downloaded cell phone data, especially given the
ubiquity of cell phones and the increasing prevalence of
personal digital data in criminal investigations.
¶78 The exclusionary rule——that evidence obtained in
violation of the Fourth Amendment be excluded from trial——
ensures that the Fourth Amendment's right to be free from
unreasonable searches remains one "of substance rather than mere
tinsel." Hoyer v. State, 180 Wis. 407, 415, 193 N.W. 89 (1923).
By excluding otherwise relevant evidence, "[t]he exclusionary
rule generally serves to 'deter deliberate, reckless, or grossly
negligent conduct, or in some circumstances recurring or
systemic negligence.'" Blackman, 377 Wis. 2d 339, ¶68 (quoting
Herring v. United States, 555 U.S. 135, 150-51 (2009)). The
rule thus incentivizes "the law enforcement profession as a
whole" to conduct itself "in accord with the Fourth Amendment."
Gates, 462 U.S. at 261 n.15 (White, J., concurring in the
judgment).
¶79 Given that critical function, the United States
Supreme Court has permitted deviation from the exclusionary rule
only when the deterrent value of excluding the evidence is
"marginal" or "nonexistent" and outweighed by the social cost of
doing so. See, e.g., United States v. Leon, 468
U.S. 897, 913-17, 922 (1984). Such is the case when there is no
police misconduct to deter or when the police misconduct is
"isolated," "nonrecurring," and "attenuated." See id. at 922;
Herring, 555 U.S. at 137, 144. For example, excluding
unlawfully obtained evidence is inappropriate if the police
acted in objectively reasonable reliance on either a facially
10
No. 2019AP1404-CR.rfd
valid warrant properly issued by a neutral, detached magistrate;
an apparently constitutional statute; or a binding appellate
precedent. See Leon, 468 U.S. 897 (warrants);4 Illinois v.
Krull, 480 U.S. 340 (1987) (statutes); Davis v. United
States, 564 U.S. 229, 239-41 (2011) (appellate precedents).
Likewise, exclusion is inappropriate when an arresting officer
acts in objectively reasonable reliance on either a judicial or
police employees' infrequent clerical mistake. See Arizona v.
Evans, 514 U.S. 1, 14-16 (1995) (court clerk made a
recordkeeping error regarding outstanding arrest warrants only
once "every three or four years"); Herring, 555 U.S. at 144-47
(police employees' clerical error in warrant database had never
happened before). The common thread through each of these cases
is that the fault lies with someone who is not directly engaged
in the "competitive enterprise of ferreting out crime"; who has
"no stake in the outcome of particular prosecutions." See
Evans, 514 U.S. at 15.
¶80 Conversely, the exclusionary rule applies when
evidence is unlawfully obtained due to an error made by law
enforcement. See Leon, 468 U.S. at 923. For instance, evidence
should be suppressed when law enforcement secures evidence based
on a facially deficient warrant, or when a warrant is issued
based on an officer knowingly or recklessly stating a falsehood
in the warrant affidavit. See id. The same goes for when
police exceed a valid warrant's authority when executing it.
See id. As for the police relying on statutory authority, the
See also Massachusetts v. Sheppard, 468 U.S. 981, 988-91
4
(1984).
11
No. 2019AP1404-CR.rfd
exclusionary rule still applies when police officers
misinterpret and "act outside the scope" of a statute and when a
reasonable officer would have known either that the law in
question is unconstitutional or that the conduct authorized by
the statute violates other clearly established law. Krull, 480
U.S. at 355, 360 n.17. Indeed, the rule applies even to
unlawfully negligent police conduct when the conduct is
"recurring or systemic." E.g., Herring, 555 U.S. at 144.
¶81 The exclusionary rule applies in this case because it
was the Sheriff's Office's conduct that rendered unlawful its
search of Burch's cell phone, not some detached third party's.
There was no statute or judicial precedent condoning a
warrantless search of another agency's download of a person's
private cell phone data. Instead, the Sheriff's Office judged
for itself, incorrectly, that the Fourth Amendment's warrant
requirement did not apply to Burch's cell phone data. The
unlawful conduct here——not obtaining a warrant to search Burch's
private cell phone data——is solely attributable to the Sheriff's
Office's detectives. And because those detectives are directly
engaged in the "competitive enterprise of ferreting out crime,"
the exclusionary rule should apply. See Evans, 514 U.S. at 15.
¶82 Applying the rule is also justified because the record
demonstrates that warrantless searches of private cell phone
information are commonplace, and therefore likely to recur.
Officers from both the GBPD and the Sheriff's Office confirmed
that it is "very common" for agencies to share "full downloads"
of private cell phones with other agencies without first
obtaining a warrant, adding that their agencies "regularly" do
12
No. 2019AP1404-CR.rfd
so. This widespread neglect of the Fourth Amendment's warrant
requirement is just the kind of "systemic negligence" the
exclusionary rule is designed to correct. See Herring, 555 U.S.
at 144. The exclusionary rule thus squarely applies here.
¶83 The State's counterarguments are unavailing. Its
contention that the Sheriff's Office reasonably relied upon its
own determination regarding the scope of Burch's consent misses
the point. It is not up to the police to determine the contours
of an exception to a constitutional requirement restricting
their own conduct. See Leon, 468 U.S. at 959 (Brennan, J.,
dissenting) (presciently lamenting that exceptions to the
exclusionary rule would not stay "confined" but instead be
wrongfully extended "to situations in which the police have
conducted a warrantless search solely on the basis of their own
judgment"). Moreover, because the police may encounter
circumstances that are on the margins of the law regarding
warrant exceptions——as is the case here——police officers are
required to "err on the side of constitutional behavior" and get
a warrant.5 See United States v. Johnson, 457 U.S. 537, 561
The State erroneously argues that the Sheriff's Office's
5
search is akin to law enforcement's ability to take a "second
look" at physical evidence inventoried during a jail intake or
that it already lawfully seized. See State v. Betterley, 191
Wis. 2d 406, 418, 529 N.W.2d 216 (1995); State v. Riedel, 2003
WI App 18, ¶16, 259 Wis. 2d 921, 656 N.W.2d 789. But as the
United States Supreme Court explained in Riley, "cell phones, as
a category, implicate privacy concerns far beyond those
implicated" by physical objects. 573 U.S. at 393. And because
a "search of the information on a cell phone bears little
resemblance" to other types of searches, the rationales for
other searches do not extend to cell phone information. See id.
at 386. Therefore, the State's arguments fail. See People v.
Hughes, 958 N.W.2d 98, 111-15 (Mich. 2020).
13
No. 2019AP1404-CR.rfd
(1982); Blackman, 377 Wis. 2d 339, ¶53 (warrantless searches
executed outside any "clearly delineated" warrant exception are
"per se unreasonable" and "unlawful"). The Sheriff's Office's
erroneous determination that Burch's consent extended to the
Sheriff's Office is no justification for failing to get a
warrant.
¶84 Nor is the Sheriff's Office relieved of its Fourth
Amendment duty to get a warrant simply because law enforcement
agencies "regularly" share this type of information. The
pervasiveness of this practice is no defense to the exclusionary
rule; it is the reason to apply it. See Herring, 555 U.S.
at 144 (exclusion applies when unreasonable police conduct is
"recurring" or "systemic"). The same goes for the majority's
characterization of the Sheriff's Office's conduct as "by the
book." Majority op., ¶22. If following "the book" leads to
violations of the Fourth Amendment, then the exclusionary rule's
deterrent value is at its peak. Excluding evidence obtained by
following such an unlawful and widespread policy provides
significant societal value by both specifically deterring
continued adherence to an unconstitutional practice and more
broadly incentivizing police agencies to adopt policies in line
with the Fourth Amendment.6 See Wayne R. LaFave, 1 Search &
Seizure § 1.3(i) (6th ed. 2020). This is especially true when
6 The State counters that because the Sheriff's Office may
have had access to Burch's Google email account and internet
search history via a lawful, independent source, that evidence
should not be excluded. See State v. Carroll, 2010
WI 8, ¶¶44-45, 322 Wis. 2d 299, 778 N.W.2d 1. But the State has
forfeited that argument by failing to raise it below. See State
v. Counihan, 2020 WI 12, ¶25, 390 Wis. 2d 172, 938 N.W.2d 530.
14
No. 2019AP1404-CR.rfd
the Constitution already provides law enforcement with a simple
solution for how to lawfully obtain cell phone data: get a
warrant. See Riley, 573 U.S. at 403.
C. The Majority Opinion Has No Support in Fourth Amendment
Jurisprudence.
¶85 The majority opinion offers a contrary analysis that
ignores the novel constitutional problems presented by cell
phone data, is inconsistent with the Fourth Amendment's text,
and undermines the exclusionary remedy.
¶86 The majority opinion's analysis reveals a lack of
appreciation for the fundamental differences between digital
cell phone data and more "traditional," non-digital evidence
that law enforcement might share with other agencies. The
Fourth Amendment treats cell phone data differently because it
often contains nearly all the "privacies of [a person's] life,"
such that "any extension" of Fourth Amendment principles "to
digital data has to rest on its own bottom." See Riley, 573
U.S. at 393, 403 (quoting another source); Carpenter, 138 S. Ct.
at 2219 (explaining that Fourth Amendment jurisprudence must
account for the "seismic shifts in digital technology").
Accordingly, it is a grave analytical error to "mechanically
apply[]" to cell phone data Fourth Amendment rationales that
were developed without such invasive technologies in mind.
Carpenter, 138 S. Ct. at 2219; see also Riley, 573 U.S.
at 400-01 (rejecting the argument that the police can search
cell phone data under the same rationale that allows them to
obtain "the same information from a pre-digital counterpart").
Or, as the United States Supreme Court put it, treating cell
15
No. 2019AP1404-CR.rfd
phone data the same as its non-digital analogues "is like saying
a ride on horseback is materially indistinguishable from a
flight to the moon. Both are ways of getting from point A to
point B, but little else justifies lumping them together."
Riley, 573 U.S. at 393. The majority opinion, however, is
content to toss a saddle on a spaceship and call it a horse.
Nowhere does the majority opinion account for Burch's special
privacy interest in his cell phone data, leaving a tremendous
hole in its exclusionary rule analysis.
¶87 More troubling is the majority's disregard for the
Fourth Amendment's text. It is bedrock Fourth Amendment law
that search warrants are generally required and that a search
without a warrant is per se unlawful. See, e.g., City of
Ontario v. Quon, 560 U.S. 746, 760 (2010); Blackman, 377
Wis. 2d 339, ¶53. The majority's assertion that "there is
nothing concerning under current Fourth Amendment doctrine with
how the Sheriff's Office detectives conducted themselves"
shockingly discards this well-settled principle. Indeed, the
majority opinion fails to even mention the presumption that
warrantless searches violate the Fourth Amendment.
¶88 But worse than mere silence, the majority's refusal to
apply the exclusionary rule flips this presumption on its head.
According to the majority, if "no case from this court or the
federal courts" directs the police to get a warrant, then the
police act "reasonably" in not getting a warrant. Majority
op., ¶23. The majority appears to create a new prerequisite for
applying the exclusionary rule, holding that it applies only if
a court has previously declared that the police conduct at issue
16
No. 2019AP1404-CR.rfd
is unconstitutional. Imposing this hurdle undermines the
exclusionary remedy for Fourth Amendment violations and is
directly contrary to both our and the United States Supreme
Court's Fourth Amendment jurisprudence.
¶89 All of which makes inexcusable the majority opinion's
refusal to address the constitutionality of the Sheriff's
Office's search. Despite law enforcement's admittedly "very
common" practice of sharing with other agencies entire downloads
of private cell phone data, that recurring Fourth Amendment
violation will continue with impunity unless and until the court
engages with the specific Fourth Amendment issue raised by
private cell phone information. By skipping straight to whether
the exclusionary rule applies, the majority opinion deprives
aggrieved defendants——and future courts——of the very prior
precedent now necessary to remedy law enforcement's continued
unconstitutional conduct:
Forgoing a knotty constitutional inquiry makes for
easier sledding, no doubt. But the inexorable result
is "constitutional stagnation"——fewer courts
establishing law at all, much less clearly doing
so, . . . [creating a] Catch-22. [Defendants] must
produce precedent even as fewer courts are producing
precedent. Important constitutional questions go
unanswered precisely because no one's answered them
before. Courts then rely on that judicial silence to
conclude there's no equivalent case law on the
books. . . . If courts leapfrog the underlying
constitutional merits in cases raising novel issues
like digital privacy, then constitutional clarity——
matter-of-fact guidance about what the Constitution
requires——remains exasperatingly elusive.
Result: gauzy constitutional guardrails as
technological innovation outpaces legal adaptation.
Zadeh v. Robinson, 928 F.3d 457, 479-80 (5th Cir. 2019)
(Willet, J., concurring), cert. denied, 141 S. Ct. 110 (2020).
17
No. 2019AP1404-CR.rfd
Together with its new prior-precedent requirement, the majority
opinion's avoidance of the Fourth Amendment issues here
perpetuates a cycle of diminished police accountability and
courts' unwillingness to address it.
¶90 Given that the Fourth Amendment law specific to cell
phone data is undeveloped, this court should be providing "clear
guidance to law enforcement through categorical rules."
Riley, 573 U.S. at 398; see also Michigan v. Summers, 452
U.S. 692, 705 n.19 (1981) (explaining that clear "workable"
rules are necessary so that difficult Fourth Amendment questions
are not resolved in an "ad hoc, case-by-case fashion by
individual police officers") (quoting another source)). If a
law enforcement agency wishes to search a person's private
information, such as cell phone data, and the person did not
consent to that agency's search, the agency must get a warrant.
III. CONCLUSION
¶91 The Sheriff's Office should have obtained a warrant to
search Burch's private cell phone data. Because it did not, the
evidence it found as a result of that search should be
suppressed. The majority's refusal to apply the exclusionary
rule is incompatible with our Fourth Amendment jurisprudence and
perverts the long-standing bedrock requirement that police
obtain a warrant to search private information. I therefore
respectfully dissent from that part of the majority opinion.
¶92 I am authorized to state that Justice JILL J. KAROFSKY
joins this opinion and that Justice ANN WALSH BRADLEY joins this
opinion except for footnote 1.
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No. 2019AP1404-CR.awb
¶93 ANN WALSH BRADLEY, J. (dissenting). Ubiquitous use
does not mean the average wearer of a Fitbit knows how it works.
Nor does ubiquitous use indicate reliability sufficient to be
admissible in a court of law.
¶94 An average jury member would likely know what a Fitbit
is and what it does. Of course, as relevant here, it counts the
wearer's steps. But that isn't the question. In determining
whether expert testimony is required, the relevant inquiry is
how a Fitbit counts the wearer's steps and then ultimately,
whether it does so with sufficient reliability.
¶95 How does it work? A Fitbit device uses a
microelectronic triaxial accelerometer to capture a person's
body motion in three-dimensional space and record related data.
This motion data is then analyzed by utilizing proprietary
algorithms to surmise patterns and thus to identify daily steps
taken.
¶96 Is it sufficiently reliable to be admitted as evidence
in court? I don't know. But, I do know that the answer does
not lie in its ubiquitous use.
¶97 I also know that absent expert testimony there is
insufficient foundation in this record for the majority to
determine, in essence, that a presumption of accuracy and
reliability attends the underlying technology of a Fitbit. The
error of such a presumption is made manifest by reference to an
overarching analysis of 67 studies on Fitbit accuracy
disseminated by the National Center for Biotechnology
Information (NCBI), under the auspices of the U.S. National
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No. 2019AP1404-CR.awb
Institutes of Health (NIH). The researchers found that Fitbit
devices were "likely to meet acceptable accuracy for step count
approximately half the time." Lynne M. Feehan, et al., Accuracy
of Fitbit Devices: Systematic Review and Narrative Syntheses of
Quantitative Data,
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6107736/ (2018).
¶98 In citing this study, I neither endorse nor disclaim
its conclusions. It suggests, however, when a compilation of
studies indicates acceptable accuracy is met only "half the
time," that something may be amiss with the majority's
presumption of accuracy and reliability.
¶99 Expert testimony is required when matters are
presented that are "unusually complex." White v. Leeder, 149
Wis. 2d 948, 960, 440 N.W.2d 557 (1989). Movement measured by a
"microelectronic triaxial accelerometer" and analyzed by
proprietary algorithms certainly fits that bill.
¶100 In my view, the technology underlying a Fitbit is not
within the ordinary experience of an average jury member.
Fitbits and other wearable devices may be ubiquitous, but it
does not follow from this premise that the technology underlying
their use is not "unusually complex."
¶101 Expert testimony assists the trier of fact to
understand the evidence and to determine a fact in issue. The
accuracy of the number of steps recorded on Douglass Detrie's
Fitbit is certainly a fact in issue. Thus, expert testimony
should have been required to assist the jury in understanding
the technology and assessing its reliability.
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No. 2019AP1404-CR.awb
¶102 Invoking a deferential standard, it is not unusual for
an appellate court to do only a cursory analysis of an
evidentiary issue. But this is not the usual case and a more
nuanced analysis is required.
¶103 This case presents a groundbreaking question. To my
knowledge, this is the first appellate court decision in the
country to conclude that Fitbit step-counting evidence is
admissible absent expert testimony explaining how the device
works. The parties have not cited, and I have not found, any
case making such a proclamation. The majority's analysis
provides a slim reed upon which to support such a novel
determination.
¶104 Rather than allowing evaluation of the question, the
majority cuts off the debate. It essentially rubber stamps the
circuit court's erroneous analysis and declares Fitbit's
technology to be simple enough to be presented as evidence
without the benefit of an expert witness or further
consideration of its reliability.
¶105 Although I join Justice Dallet's dissent, concluding
that the search of Burch's cell phone at issue violated his
Fourth Amendment rights and that the good faith exception to the
warrant requirement does not apply, I do not join footnote 1
that concurs with the majority's analysis of the Fitbit
evidence. Because I conclude that the circuit court erroneously
admitted the Fitbit evidence without an expert witness to
establish the reliability of the science underlying the Fitbit
technology, I respectfully dissent.
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No. 2019AP1404-CR.awb
I
¶106 I briefly recount the facts that are relevant to the
issue on which I write: the admission of the Fitbit evidence.
¶107 As the majority opinion sets forth, the initial
suspect in the crime at issue here was Douglass Detrie, the
victim's boyfriend. Majority op., ¶4. However, the
investigation shifted after police learned that Detrie's Fitbit
device had recorded only 12 steps during the time the homicide
was committed. Burch was ultimately arrested and charged.
¶108 The State sought to present evidence regarding
Detrie's Fitbit, and Burch moved to exclude it. Id., ¶11. As
relevant here, Burch contended that the State must present
expert testimony to establish the reliability of the science
behind the Fitbit device. Id.1
¶109 The circuit court granted Burch's motion in part and
denied it in part. Specifically, the circuit court excluded
Fitbit evidence related to sleep monitoring, but it allowed the
admission of the step-counting data without the testimony of an
expert regarding the science underlying the Fitbit technology.
Id., ¶11 & n.3.
¶110 In the circuit court's estimation, a Fitbit is more
akin to an electronic monitoring device (which does not require
expert testimony, see State v. Kandutsch, 2011 WI 78, 336
1 Burch made several additional arguments, including an
assertion that Fitbit's records were not properly authenticated,
which he renews on appeal. Because I determine that expert
testimony was necessary to admit the evidence in question, I do
not reach Burch's arguments regarding authentication.
4
No. 2019AP1404-CR.awb
Wis. 2d 478, 799 N.W.2d 865) than to a preliminary breath test
(which requires expert testimony, see State v. Doerr, 229
Wis. 2d 616, 599 N.W.2d 897 (Ct. App. 1999)). Similarly, the
circuit court distinguished Fitbit data from DNA, fingerprint
analysis, blood alcohol content tests, tool mark evidence and
accident reconstruction because "few people encounter those
things in their everyday life."
¶111 Comparing a Fitbit to an electronic monitoring device,
the circuit court stated that a Fitbit is "passively worn by a
person," and the device collects data "based on that person's
movements, which is then transmitted and recorded. There is no
active manipulation by the wearer to achieve the results; the
results are simply a record of the wearer's movements, i.e.,
their location or the number of steps they took." Thus, in the
circuit court's view "the step-counting feature of the Fitbit
Flex, like the [electronic monitoring device], is not so
unusually complex or esoteric that the jury will require the aid
of expert testimony to interpret the information."
¶112 At trial, because it was not required to provide an
expert to introduce the data from Detrie's Fitbit, the State
relied upon the testimony of Tyler Behling, a computer forensic
crime analyst with the Brown County Sheriff's Office. Although
Behling claimed to have knowledge of how a Fitbit works "on a
high level," he did not know the answer when asked how a Fitbit
and a Bluetooth device send information from one to the other,
how Fitbit stores its data, whether Fitbit data can be edited,
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No. 2019AP1404-CR.awb
whether the device would register steps while it is not being
worn, or what a Fitbit's error rate is.
¶113 Despite the dearth of technical testimony regarding
how a Fitbit actually works, the majority now affirms the
circuit court's determination. It concludes that "[g]iven the
widespread availability of Fitbits and other similar wireless
step-counting devices in today's consumer marketplace, the
circuit court reasonably concluded Detrie's Fitbit was not so
'unusually complex or esoteric' that the jury needed an expert
to understand it." Majority op., ¶31.
II
¶114 It has long been the law that expert testimony is
required when a matter involves "special knowledge or skill or
experience on subjects which are not within the realm of the
ordinary experience of mankind, and which require special
learning, study and experience." Cramer v. Theda Clark Mem'l
Hosp., 45 Wis. 2d 147, 150, 172 N.W.2d 427 (1969). "The
requirement of expert testimony is an extraordinary one," and
should be applied "only when unusually complex or esoteric
issues are before the jury." White, 149 Wis. 2d at 960.
¶115 "In considering what constitutes the 'ordinary
experience of mankind'——i.e. the average juror——courts have not
tailored this standard to the lowest common denominator.
Rather, courts attempt to evaluate, on a case-by-case basis,
whether expert testimony is required because the issue is
outside the realm of lay comprehension." Kandutsch, 336
Wis. 2d 478, ¶29.
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No. 2019AP1404-CR.awb
¶116 The circuit court here determined that the technology
underlying a Fitbit is not outside the realm of lay
comprehension. It compared a Fitbit to a watch in that "the
public generally understands the principle of how it functions
and accepts its reliability without knowing the exact mechanics
of its internal workings." Further, it determined that a Fitbit
is not subject to "active manipulation by the wearer to achieve
the results; the results are simply a record of the wearer's
movements, i.e., their location or the number of steps they
took."
¶117 But the expert testimony standards do not rest on
ubiquity. Instead, they rest on the complexity of the subject
matter. Although many members of the jury may have been wearing
Fitbits or similar devices, such a fact would not inform the
question of whether those jury members understand how a Fitbit
works or whether the technology is reliable.
¶118 What does the average person really know about how a
Fitbit works, much less its reliability? As one study described
it, "Fitbit devices use a microelectronic triaxial accelerometer
to capture body motion in 3-dimensional space, with these motion
data analyzed using proprietary algorithms to identify patterns
of motion to identify daily steps taken, energy expenditure,
sleep, distance covered, and time spent in different intensity
of activities." Feehan, et al., supra. According to the
majority, the average juror would understand, without expert
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No. 2019AP1404-CR.awb
testimony, not only what a "microelectronic triaxial
accelerometer" is, but how it works. Really?2
¶119 If the State had presented an expert, that expert
would have had to meet the requirements for expert testimony
established by the United States Supreme Court in Daubert.3
Pursuant to the Daubert standard, as codified in Wis. Stat.
§ 907.02(1),4 the circuit court must act as a gatekeeper and make
a threshold determination that the testimony is reliable in
order for it to be presented at trial. State v. Dobbs, 2020 WI
64, ¶43, 392 Wis. 2d 505, 945 N.W.2d 609. By not requiring the
State to present an expert, the circuit court and the majority
allow the State to skirt this initial reliability determination.
¶120 There are various ways in which threshold reliability
can be demonstrated. See 7 Daniel D. Blinka, Wisconsin Practice
Series: Wisconsin Evidence § 702.402 (4th ed. 2020). There may
2Further, the intricacies of Fitbit's technology are
"proprietary," setting up an additional roadblock to the jury's
full knowledge and full understanding of how the device works.
See State v. Loomis, 2016 WI 68, ¶66, 371 Wis. 2d 235, 881
N.W.2d 749 (explaining that "proprietary nature" has been
invoked to prevent disclosure of certain information).
3 Daubert v. Merrell Dow Pharm., Inc., 509 U.S. 579 (1993).
4 Wisconsin Stat. § 907.02(1) provides:
If scientific, technical, or other specialized
knowledge will assist the trier of fact to understand
the evidence or to determine a fact in issue, a
witness qualified as an expert by knowledge, skill,
experience, training, or education, may testify
thereto in the form of an opinion or otherwise, if the
testimony is based upon sufficient facts or data, the
testimony is the product of reliable principles and
methods, and the witness has applied the principles
and methods reliably to the facts of the case.
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No. 2019AP1404-CR.awb
be a statute indicating that certain tests or methods are
admissible. See, e.g., Wis. Stat. § 885.235 (addressing
chemical tests for intoxication). There is no statute
addressing Fitbit evidence.
¶121 We can also look to court precedent which has already
determined certain principles to be reliable. See, e.g., State
v. Hanson, 85 Wis. 2d 233, 244, 270 N.W.2d 212 (1978)
(discussing the reliability of the underlying principles of
speed radar detection that employs the Doppler effect). The
reliability of Fitbit's step counting capability is a novel
issue, so there is no precedent on point.
¶122 Stipulations or judicial notice may also be
appropriate when a fact is "capable of accurate and ready
determination by resort to sources whose accuracy cannot
reasonably be questioned." Wis. Stat. § 902.01(2)(b). Again,
these do not fit the present scenario——the reason we are here is
because the parties do not agree and Burch reasonably questions
the accuracy of Fitbit's step count.
¶123 Finally, if none of the above proves to be an
acceptable avenue to demonstrate the accuracy and reliability of
the scientific principles sufficient to be accorded a prima
facie presumption, expert testimony is necessary to explain the
underlying scientific principles and to demonstrate their
reliability. Here, no expert was presented.
¶124 The evidentiary process requires that the scientific
principles be presented to the court before the evidence is
determined to be reliable. In a court of law, process matters.
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No. 2019AP1404-CR.awb
Without fulfilling one of these avenues, the threshold
reliability determination cannot be made.
¶125 And what of Fitbit's reliability? Such reliability
can depend on a number of factors, such as whether the user has
self-manipulated the data, if the Fitbit is temporarily removed,
where on the body the device is worn, or the type of physical
activity in which the wearer is engaged. Feehan, et al., supra;
Katherine E. Vinez, The Admissibility of Data Collected from
Wearable Devices, 4 Stetson J. Advoc. & L. 1, 16 (2017). In a
comprehensive aggregation of 67 different studies, researchers
found that "[c]onsistent evidence indicated that Fitbit devices
were likely to meet acceptable accuracy for step count
approximately half the time." Feehan, et al., supra. Yet in
the view of the majority and of the circuit court, an expert is
not necessary to establish the reliability of Detrie's step
count——the Fitbit evidence can go before the jury with no
technical or scientific explanation.
¶126 Indeed, questions arise about the reliability of
wearable devices despite their widespread acceptance. See
Vinez, supra, at 16. If reliability questions exist, where
better than the circuit court to present the case for and
against such reliability? Instead of remanding to the circuit
court for evaluation of the question, the majority curtly
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No. 2019AP1404-CR.awb
declares Fitbit's technology to be simple enough to be put
before a jury without the benefit of an expert.5
¶127 When new and popular devices emerge, courts should be
wary of blindly accepting the data they produce without a
thorough examination of the underlying technology. "Machines
warrant no blind faith, and whatever trust they receive must be
earned through the crucible of the rules of evidence." Brian
Sites, Machines Ascendant: Robots and the Rules of Evidence, 3
Geo. L. Tech. Rev. 1, 1-2 (2018). In many cases, such an
examination will require an expert. In my view, this is such a
case.
¶128 Rather than break new ground as does the majority, I
would proceed with caution. Basing the necessity of expert
testimony on ubiquity rather than complexity sets a dangerous
path.
¶129 For the foregoing reasons, I respectfully dissent.
See Nicole Chauriye, Wearable Devices as Admissible
5
Evidence: Technology is Killing our Opportunities to Lie, 24
Cath. U. J. L. & Tech. 495, 517 (2016) (arguing that "the trier
of fact would greatly benefit from mandated expert testimony to
explain the accuracy and details of the data recorded by the
wearable technology").
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1