[J-12-2023] [MO: Todd, C.J.]
IN THE SUPREME COURT OF PENNSYLVANIA
WESTERN DISTRICT
COMMONWEALTH OF PENNSYLVANIA, : No. 19 WAP 2022
:
Appellee : Appeal from the Order of the
: Superior Court entered May 26,
: 2021 at No. 582 WDA 2020,
v. : affirming the Judgment of Sentence
: of the Court of Common Pleas of
: Allegheny County entered February
ANGELO WEEDEN, : 24, 2020 at No. CP-02-CR-
: 0000513-2019.
Appellant :
: ARGUED: April 18, 2023
CONCURRING OPINION
JUSTICE WECHT DECIDED: NOVEMBER 16, 2023
ShotSpotter’s proprietary gunshot-detection system is a network of acoustic
sensors that is installed throughout a neighborhood to aid and facilitate law enforcement’s
response to gun violence.1 When potential gunfire is detected, sensors record the time
and capture an audio recording of the sound.2 Two artificial intelligence algorithms
immediately assess the data in order to triangulate the location of the sounds and to filter
1 ShotSpotter FAQs, SoundThinking, www.soundthinking.com/law-
enforcement/gunshot-detection-technology (last visited Sept. 7, 2023) [hereinafter
ShotSpotter FAQs]. ShotSpotter was founded in 1996. About SoundThinking,
SoundThinking, https://www.soundthinking.com/company/ (last visited Sept. 14, 2023).
In 2023, in order to reflect its expansion to include a broader spectrum of law enforcement
tools, ShotSpotter underwent a corporate rebranding, and now calls itself
“SoundThinking.” Id. However, the company retained “ShotSpotter” as the name of the
proprietary technology at issue in this case. Id.
2 ShotSpotter FAQs.
out noises that are not gunshots (such as fireworks).3 The information generated by these
algorithms is immediately reviewed and interpreted by a trained ShotSpotter employee in
California. Within approximately sixty seconds (or less), the analyst listens to the audio
recording and conducts a “visual analysis of the waveform.”4 If the analyst determines
that the noise was, in fact, the sound of gunfire, he or she immediately alerts local law
enforcement.5
ShotSpotter compiles all of this information into an “Investigative Lead Summary.”
The data in this document reflects the input of at least one of ShotSpotter’s trained
analysts, who are known as “Incident Reviewers.”6 ShotSpotter admits that the data in
the summary is unreliable, and that it should not be used for anything other than initial
investigative purposes.7 Although these summaries are modified by human input and are
not amenable to cross-examination, they are introduced as substantive evidence at
criminal trials—including in the case at bar—in order to prove that a defendant, in fact,
fired a gun at a particular time and location.8
3 SoundThinking Responds to False Claims, SoundThinking,
https://www.soundthinking.com/soundthinking-responds-to-false-claims (last visited
Sept. 14, 2023).
4 Id.
5 ShotSpotter FAQs.
6 Appellant’s Br. App. D, at 3 (“Machine learning algorithms analyze and classify the
sounds before they are reviewed by acoustic experts at the Incident Review Center.”).
7 See id. at 2 (“The number of individual shots below may not match the round count
reported on page one if an Incident Reviewer adjusted the round count during incident
review prior to publication.”); id. at 3 (“Although it provides precise trigger-pull location
and timing as determined automatically by the ShotSpotter system, this summary should
only be used for initial investigative purposes because the shot timing, location, and count
could differ once reviewed by a ShotSpotter Forensic Engineer.”).
8 That ShotSpotter documentation is used as a trial tool is not merely an incidental
byproduct of using its system. To the contrary, ShotSpotter, in part, markets itself for
(continued…)
[J-12-2023] [MO: Todd, C.J.] - 2
Admitting these out-of-court statements as substantive evidence undermines each
of the foundational interests underlying the Confrontation Clause of the Sixth Amendment
to the United States Constitution.9 However, as the Majority aptly explains,10 the “primary
purpose” of the Investigative Lead Summary is to assist law enforcement in responding
to, and subsequently investigating, an “ongoing emergency,”11 not “to establish or prove
past events potentially relevant to later criminal prosecution.”12 Thus, the Investigative
Lead Summary is nontestimonial, and, pursuant to the United States Supreme Court’s
precedents, can be admitted at trial without cross-examination and without running afoul
of the Confrontation Clause.13 Bound by those precedents, I join the Majority’s opinion.
I write separately to highlight the inequity that results from treating nontestimonial
statements differently than testimonial ones under the Confrontation Clause.
such use. SoundThinking advertises on its website that it provides “Litigation Support”
for prosecutors through its “Investigative Lead Summaries” and “Detailed Forensic
Reports.” ShotSpotter Forensic Services, SoundThinking,
https://www.soundthinking.com/law-enforcement/leading-gunshot-detection-system (last
visited Sept. 14, 2023). SoundThinking also offers “Expert Witness Services” to assist
prosecutors in preparing for trial or to provide expert witness testimony. Id.
9 The Confrontation Clause of the Sixth Amendment to the United States
Constitution states that, “[i]n all criminal prosecutions, the accused shall enjoy the
right . . . to be confronted with the witnesses against him.” U.S. Const. amend VI.
Similarly, the Pennsylvania Constitution provides that, “[i]n all criminal prosecutions the
accused hath a right . . . to be confronted with the witnesses against him.” Pa. Const. art.
I, § 9. Although Weeden invokes both Constitutions, he does not argue that
Pennsylvania’s Confrontation Clause provides greater protections than its federal
counterpart.
10 See Majority Op. at 28-29.
11 See Davis v. Washington, 547 U.S. 813, 822 (2006).
12 Id.
13 See Majority Op. at 28-29.
[J-12-2023] [MO: Todd, C.J.] - 3
The Confrontation Clause of the Sixth Amendment, and the concomitant right to
cross-examination of adverse witnesses, are “bedrock procedural guarantee[s]”14 that are
an “essential and fundamental requirement for the kind of fair trial which is this country’s
constitutional goal.”15 “The fact that this right appears in the Sixth Amendment of our Bill
of Rights reflects the belief of the Framers of those liberties and safeguards that
confrontation was a fundamental right essential to a fair trial in a criminal prosecution.”16
Thus, “[i]n the constitutional sense,” evidence in a criminal trial “shall come from the
witness stand in a public courtroom where there is full judicial protection of the defendant’s
right of confrontation, of cross-examination, and of counsel.”17
The Confrontation Clause operates “to ensure the reliability of the evidence against
a criminal defendant by subjecting it to rigorous testing in the context of an adversar[ial]
proceeding before the trier of fact.”18 “The word ‘confront,’ after all, also means a clashing
of forces or ideas . . . .”19
The primary object of the [Confrontation Clause] was to prevent depositions
or ex parte affidavits, such as were sometimes admitted in civil cases, being
used against the prisoner in lieu of a personal examination and cross-
examination of the witness, in which the accused has an opportunity, not
only of testing the recollection and sifting the conscience of the witness, but
of compelling him to stand face to face with the jury in order that they may
look at him, and judge by his demeanor upon the stand and the manner in
which he gives his testimony whether he is worthy of belief.20
14 Crawford v. Washington, 541 U.S. 36, 42 (2004).
15 Pointer v. Texas, 380 U.S. 400, 405 (1965).
16 Id. at 404.
17 Turner v. Louisiana, 379 U.S. 466, 472-73 (1965).
18 Maryland v. Craig, 497 U.S. 836, 845 (1990).
19 Id.
20 Mattox v. United States, 156 U.S. 237, 242-43 (1895).
[J-12-2023] [MO: Todd, C.J.] - 4
Thus, the Confrontation Clause ensures not only a “personal examination” of a
testifying witness,21 but it also:
(1) insures [sic] that the witness will give his statements under oath—thus
impressing him with the seriousness of the matter and guarding against the
lie by the possibility of a penalty for perjury; (2) forces the witness to submit
to cross-examination, the greatest legal engine ever invented for the
discovery of truth; [and] (3) permits the jury that is to decide the defendant’s
fate to observe the demeanor of the witness in making his statement, thus
aiding the jury in assessing his credibility.22
An accused can take advantage of these “bedrock procedural guarantee[s]”23 only
when a person with first-hand knowledge of the evidence testifies “from the witness stand
in a public courtroom.”24 The Confrontation Clause’s protections fall to the wayside when
the evidence being offered is an out-of-court statement. A document, a tape-recording,
or the like cannot be cross-examined. Nonetheless, the concern for proof of guilt by “ex
parte affidavits”25 notwithstanding, the Supreme Court of the United States has never held
that an accused’s inability to cross-examine such evidence is a per se barrier to its
admission. Instead, the Court hinges admissibility upon the reason that the out-of-court
statement was created.
Initially, the Court held that the Confrontation Clause did not prohibit the use of out-
of-court statements as substantive evidence so long as the statement “bears adequate
21 Id. at 242.
22 California v. Green, 399 U.S. 149, 158 (1970) (footnote and internal quotation
marks omitted).
23 Crawford, 541 U.S. at 42.
24 Turner, 379 U.S. at 473.
25 Mattox, 156 U.S. at 242.
[J-12-2023] [MO: Todd, C.J.] - 5
‘indicia of reliability.’”26 The proponent of such evidence could establish its reliability by
proving to a court satisfactorily that the evidence fell “within a firmly rooted hearsay
exception,” or, if no such exception applied, that it otherwise exhibited “particularized
guarantees of trustworthiness.”27 This standard reigned in courtrooms throughout the
nation for nearly twenty-five years, until the Court reversed course in its seminal decision
in Crawford v. Washington.
In Crawford, the Court, concerned that Roberts’s reliability-focused test “stray[ed]
from the original meaning of the Confrontation Clause,”28 reconsidered the complicated
interplay between that Clause and the admissibility of an unavailable witness’s out-of-
court statement. The text of the Clause, the Court noted, shed no meaningful light on the
problem and, thus, the Court explored the common law history of the right to confront
“witnesses.”29 From that historical account, the Court discerned two “inferences about
the meaning of the Sixth Amendment.”30
First, the Court determined, “the principle evil at which the Confrontation Clause
was directed was the civil-law mode of criminal procedure, and particularly its use of ex
parte examinations as evidence against the accused.”31 The Court stressed that the
Framers’ concern with the use of ex parte affidavits as evidence in criminal cases
indicated their intent that the protections afforded by the Clause apply not only to “in-court
26 Ohio v. Roberts, 448 U.S. 56, 66 (1980) (quoting Mancusi v. Stubbs, 408 U.S. 204,
213 (1972)).
27 Id.
28 Crawford, 541 U.S. at 42.
29 Id. at 42-50.
30 Id. at 50.
31 Id.
[J-12-2023] [MO: Todd, C.J.] - 6
testimony,” but also to a “specific type of out-of-court statement.”32 Thus, the focus of the
Clause is not, as the Court held in Roberts, upon reliability, but instead upon whether the
contested statement came from a “witness,” or, put differently, someone who “bears
testimony.”33 The correct constitutional inquiry, the Court held, is whether a statement is
“testimonial” in nature, not whether it might be admissible under some “modern hearsay
rule”.34 Although the Court did not offer a comprehensive definition at the time, it did note
that, “typically,” the term “testimony” is understood as a “solemn declaration or affirmation
made for the purpose of establishing or proving some fact.”35 That is, “[a]n accuser who
makes a formal statement to government officers bears testimony in a sense that a person
who makes a casual remark to an acquaintance does not.”36 Examples of this “core class”
of testimonial statements include “ex parte in-court testimony or its functional
equivalent— . . . affidavits, custodial examinations, prior testimony that the defendant
was unable to cross-examine . . . .”37
Second, the Court inferred from its historical examination that “the Framers would
not have allowed admission of testimonial statements of a witness who did not appear at
trial unless he was unavailable to testify, and the defendant had had a prior opportunity
for cross-examination.”38 The opportunity to cross-examine a witness about a
“testimonial” statement is not “merely one of several ways to establish reliability,” but
32 Id. at 50-51.
33 Id. at 51.
34 Id.
35 Id.
36 Id.
37 Id. (citations omitted).
38 Id. at 53-54.
[J-12-2023] [MO: Todd, C.J.] - 7
instead is the dispositive “condition for admissibility.”39 Therefore, the admissibility of an
out-of-court statement for Confrontation Clause purposes depends entirely upon whether
that statement was “testimonial,” and not upon “amorphous notions” of reliability, 40 or
upon a “malleable standard” that scrutinizes a statement for “particularized guarantees of
trustworthiness.”41 Thus, the Crawford Court overruled Roberts and reoriented the
Confrontation Clause jurisprudence to focus upon the “testimonial” character of an out-
of-court statement, and not upon its reliability.
In a series of cases decided in the wake of Crawford, the Court examined a variety
of evidentiary issues in an effort to define what makes a statement “testimonial.”42 The
Court settled on the “primary purpose” test, which defines a statement as “nontestimonial”
when it is made “under circumstances objectively indicating that the primary purpose” of
the statement is to “enable police assistance to meet an ongoing emergency.”43 On the
other hand, a “testimonial” statement is one made under circumstances that “objectively
indicated that there is no such ongoing emergency, and that the primary purpose of the
39 Id. at 55-56.
40 Id. at 61.
41 Id. at 60 (citations omitted).
42 See Davis, 547 U.S. at 828, 834 (2006) (finding that a statement made by a
domestic violence victim in the form of an affidavit prepared for police was testimonial,
while another domestic violence victim’s statement made during a 911 call was not);
Melendez-Diaz v. Massachusetts, 557 U.S. 305, 311 (2009) (holding that “certificates of
analysis” identifying a substance as a controlled substance were testimonial); Bullcoming
v. New Mexico, 564 U.S. 647, 652 (2011) (concluding that a blood alcohol concentration
report was testimonial, which, to be admissible, required the analysist—not a surrogate—
who conducted the testing and prepared the report to testify at trial); Michigan v. Bryant,
562 U.S. 344, 377-78 (2011) (explaining that a shooting victim’s statement to police hours
before dying was not testimonial because the statement was made for the purpose of
assisting the police during an ongoing emergency).
43 Davis, 547 U.S. at 822.
[J-12-2023] [MO: Todd, C.J.] - 8
interrogation is to establish or prove past events potentially relevant to [a] later criminal
prosecution.”44
The Investigative Lead Summary at issue in the instant case contains data
collected on December 15, 2018 at 2:43 p.m., the date and time of the alleged shooting.45
The summary provides a map and an address of the location at which ShotSpotter’s audio
sensors detected the sound of gunshots.46 The summary also contains audio files
permitting the recipient to listen to the recordings captured by the sensors.47 The
summary provides three such files.48 Next, the document identifies two of those sounds
as verified gunshots, and provides an email address for the “Incident Reviewer” who first
reviewed the three sounds, identified them initially as gunshots, and alerted the Pittsburgh
Police.49
Notably, the Investigative Lead Summary lists the “Report Date” as July 3, 2019,
which is approximately six months after the incident in question.50 Based upon this gap
in time, there is at least a colorable argument that the actual document that was submitted
to the jury in this case was not generated in response to an ongoing emergency, but
instead was created six months later, long after any such emergency dissipated. Thus, I
do not agree with the Majority that the “Report Date” is “irrelevant.”51 Nonetheless, the
44 Id.
45 Appellant’s Br. App. D, at 2.
46 Id.
47 Id. at 1.
48 Id.
49 Id. at 2.
50 Id. at 1.
51 See Majority Op. at 27 n.24.
[J-12-2023] [MO: Todd, C.J.] - 9
argument ultimately fails. The record contains no evidence to suggest that the “Report
Date” was anything other than the date that the summary either was printed or distributed
to the party that requested it. All of the information contained in the Investigative Lead
Summary was generated and collected within sixty seconds of ShotSpotter’s initial
detection of potential gunfire, and all of that data was stored within ShotSpotter’s
computer system. Producing that information in document form is no different than
providing an investigating police officer with a copy of a recording of a 911 call.52 Doing
so does not change the fact that the substance of the report, like a 911 call, was created
in response to an ongoing emergency. Lacking any indication to the contrary, I conclude
that the “Report Date” was merely the date the report was printed or transmitted to the
requesting law enforcement officer, and not the date of the report’s actual creation.
Thus, pursuant to the Supreme Court’s Confrontation Clause jurisprudence, this
out-of-court statement must be deemed to be nontestimonial, and, accordingly,
admissible against Weeden as substantive evidence, as the Majority holds. We have no
choice but to adhere to the United States Supreme Court’s precedents on matters of
United States constitutional law. I write separately to suggest that there are troubling
consequences of doing so.
As noted above, the core function of the Confrontation Clause is to “ensure the
reliability of the evidence against a criminal defendant”53 by ensuring that a criminal
defendant is afforded an opportunity to test the state’s evidence thorough cross-
52 See Davis, 547 U.S. at 828 (holding that victim’s statements during 911 call were
non-testimonial).
53 Craig, 497 U.S. at 845.
[J-12-2023] [MO: Todd, C.J.] - 10
examination, “the greatest legal engine ever invented for the discovery of truth.”54 This
guarantee is “essential to a fair trial.”55 The Crawford Court explained that:
the Clause’s ultimate goal is to ensure reliability of evidence, but it is a
procedural rather than a substantive guarantee. It commands, not that
evidence be reliable, but that reliability be assessed in a particular manner:
by testing in the crucible of cross-examination. The Clause thus reflects a
judgment, not only about the desirability of reliable evidence (a point on
which there could be little dissent), but about how reliability can best be
determined. Cf. 3 [W.] Blackstone, Commentaries [on the Laws of
England], at 373 [(1768)] (“This open examination of witnesses . . . is much
more conducive to the clearing up of truth”); M. Hale, History and Analysis
of the Common Law of England 258 (1713) (adversarial testing “beats and
bolts out the Truth much better”).56
In other words, the Confrontation Clause safeguards fair trials by requiring that the
evidence used against a criminal defendant be subject to rigorous and effective
examination by competent legal counsel. In light of this constitutional command, whether
by its text or its history, the Sixth Amendment excludes from trial testimonial out-of-court
statements, unless the author of such a statement is subject to cross-examination.
According to the Supreme Court, the Confrontation Clause applies differently to
nontestimonial statements. However, the broader purpose of the Confrontation Clause
does not change, i.e. ensuring that each criminal defendant is afforded a fair trial by
guaranteeing him or her the right to test the reliability of evidence at trial, regardless of
the testimonial or nontestimonial nature of the evidence. As such, it appears incongruous
that the availability of this fundamental protection would turn entirely upon the testimonial
character of the evidence. The Investigative Lead Summary at issue in this case is an
54 Green, 399 U.S. at 158 (quoting 5 J. Wigmore, Evidence § 1367 (3d ed. 1940)).
55 Pointer, 380 U.S. at 404.
56 Crawford, 541 U.S. at 61-62.
[J-12-2023] [MO: Todd, C.J.] - 11
apt example of why this bifurcation not only fails to further the goals of the Confrontation
Clause, but actually undermines them.
In this case, the Commonwealth alleged that Weeden fired four gunshots at the
victim’s vehicle. This fact was contested at trial. When the police investigated the scene
of the crime, they found no shell casings, bullets, or other evidence that gunshots in fact
were fired at that location. However, there were two bullet holes in the victim’s vehicle.
Weeden presented an alibi defense, claiming that he was eating chicken noodle soup at
his then-girlfriend’s house and playing video games with her son. In order to prove
definitively that Weeden fired a gun at that time and place, the Commonwealth was
permitted to introduce to the jury as substantive evidence—that is, for the truth of the
matter asserted—the ShotSpotter Investigative Lead Summary, over Weeden’s
objection.
That the Investigative Lead Summary is nontestimonial does not, ispo facto, mean
that the document should be admitted without cross-examination and without regard to
the fundamental purposes of the Confrontation Clause. To the contrary, the summary
bears many of the hallmarks of the type of unreliable evidence for which the Confrontation
Clause is designed to test.
The Investigative Lead Summary is not an automatically created dataset that is
generated by an entirely computerized or digital system, 57 as the Commonwealth argues
and as the lower courts found. Only the initial stages of a ShotSpotter “hit” involve
automated systems. The system is triggered when an acoustic sensor detects the sound
of a potential gunshot. That noise then is interpreted by two computer algorithms. The
57 See, e.g., Commonwealth v. Wallace, 289 A.3d 894, 895-96 (Pa. 2023) (holding
that the automated production of GPS data was not a “statement” for hearsay purposes,
as there is no declarant).
[J-12-2023] [MO: Todd, C.J.] - 12
automation ends there, and, “[w]ithin seconds,”58 ShotSpotter’s human analysts take
over.
As Detective Richard Baumgart, who has received extensive ShotSpotter training,
explained, every gunshot-like sound that is detected by one of ShotSpotter’s acoustic
sensors “travel[s] through a human operator.”59 The detective “believe[d]” that the
Investigative Lead Summary submitted as evidence in this case was reviewed and altered
by a human analyst, because his training and experience has taught him that all
ShotSpotter data is “sent to their human operators for review,” and that “everything that
comes back to us as being gunshots has been reviewed by a human reviewer.”60
The Investigative Lead Summary itself confirms that what the jury ultimately sees
has been reviewed, and likely amended or adjusted, by a human analyst. The report
contains a section entitled “INDIVIDUAL SHOTS.”61 This section follows the audio
recording files and lists the number of gunshots that the human analyst identified from the
noises captured in the audio recordings. The section also shows the date, time, and
location of the shots, as well as the time intervals between the shots. Adjacent to this
section on the summary, ShotSpotter cautions that:
[t]he following shot count, times, and locations were automatically
calculated by the ShotSpotter system at the time of detection. They are
approximate and should be deemed as such. The number of individual
shots below may not match the round count reported on page one if
an Incident Reviewer adjusted the round count during incident review
58 Notes of Testimony (“N.T.”) at 95, Dec. 4, 2019.
59 Id. at 93.
60 Id. at 104, 107.
61 Appellant’s Br. App. D, at 2.
[J-12-2023] [MO: Todd, C.J.] - 13
prior to publication. Some shots may overlap or hide other shots on the
map.62
Then, in the “DISCLAIMER” section of the report, ShotSpotter states the following:
The Investigative Lead Summary is produced using data automatically
generated by the ShotSpotter system and has not been independently
reviewed by our Forensic Engineers. Although it provides precise trigger-
pull location and timing as determined automatically by the ShotSpotter
system, this summary should only be used for initial investigative
purposes because the shot timing, location, and count could differ
once reviewed by a ShotSpotter Forensic Engineer. Factors, such as
obstructed or attenuated muzzle blast, weapon discharge in an enclosed
space, or if the weapon discharged is of .25 or smaller caliber, may prevent
the sensor(s) from detecting all or some of the shots fired. This summary
has been generated solely for the purpose for which it is provided. Nothing
herein shall to any extent substitute for the independent investigation of the
shooting incident. The data and conclusions herein should be corroborated
with other evidentiary sources such as recovered shell casings and witness
statements.63
In the “ABOUT SHOTSPOTTER” section, ShotSpotter once more explains that
there is human involvement in the creation of the summary:
ShotSpotter uses strategically placed acoustic sensors to detect and locate
gunshots within a coverage area. The locations of the gunshots are
calculated using audio pulse data and multilateration. Machine learning
algorithms analyze and classify the sounds before they are reviewed by
acoustic experts at the Incident Review Center. Within seconds,
Incident Reviewers add relevant tactical intelligence and publish
confirmed gunshots to ShotSpotter subscribers..64
Finally, ShotSpotter describes the human element of its process on its website:
ShotSpotter uses an array of acoustic sensors that are connected wirelessly
to ShotSpotter’s centralized, cloud-based application to reliably detect and
accurately locate gunshots using triangulation. Each acoustic sensor
captures the precise time and audio associated with impulsive sounds that
62 Id. (emphasis added).
63 Id. at 3 (emphasis added).
64 Id. (emphasis added).
[J-12-2023] [MO: Todd, C.J.] - 14
may represent gunfire. This data is used to locate the incident and is then
filtered by sophisticated machine algorithms to classify the evident as a
potential gunshot. Acoustic experts, who are located and staffed in
ShotSpotter’s 24x7 Incident Review Center, ensure and confirm that
the events are indeed gunfire. They can append the alert with the other
critical intelligence such as whether a fully automatic weapon was
fired or whether there are multiple shooters. This entire process takes
less than 60 seconds from the time of the shooting to the digital alert
popping onto a screen of a computer in the 911 Call Center or on a patrol
officer’s smartphone or mobile laptop.65
Proof that the data in the Investigative Lead Summary at issue in this case
“travel[ed] through a human operator”66 is evident on the face of the document. First, on
the second page of the summary, the “INCIDENT TIMELINE” section identifies an
individual that “published” the timeline by the email address
“REVIEWER@SHOTSPOTTER.COM.”67 Second, the summary contains three audio
recordings that captured three potential gunshot sounds. However, the “INDIVIDUAL
SHOTS” section indicates that only two of those sounds were interpreted to be actual
gunshots by a human analyst. In other words, what occurred is precisely what
ShotSpotter explained would happen. “The number of individual shots” did not “not match
the round count reported on page one” because “an Incident Reviewer adjusted the round
count during incident review prior to publication.”68 Thus, there is ample evidence that
the summary was created in large part through significant human input.
Consequently, the trial court in this case was plainly incorrect when it concluded
that the summary in this case was “unmodified by the person who reviewed the recorded
65 ShotSpotter FAQs .
66 N.T. at 93, Dec. 4, 2019.
67 Appellant’s Br. App. D, at 2.
68 Id.
[J-12-2023] [MO: Todd, C.J.] - 15
sound.”69 The Superior Court made the same mistake.70 This fundamental misreading
(or misunderstanding) of the document also led those courts erroneously to conclude that
there was no person that Weeden could confront.71 The ShotSpotter analyst who listened
to the audio recordings, used his or her “hundreds of hours of training”72 to decipher which
of those sounds were, in fact, gunshots, and reported his or her conclusions in the
Investigative Lead Summary—all of which subsequently was presented as untested
substantive evidence of a contested, critical fact at trial—is that person.
The problem here is not that no such person exists, as the lower courts believed.
The problem is that the law currently does not require the Commonwealth to put that
person on the witness stand and require that his or her interpretation of the noises and
the resulting conclusions be tested through cross-examination. The analyst was not
subject to a “personal examination”73 that:
(1) insures [sic] that the witness will give his statements under oath—thus
impressing him with the seriousness of the matter and guarding against the
lie by the possibility of a penalty for perjury; (2) forces the witness to submit
to cross-examination, the greatest legal engine ever invented for the
discovery of truth; [and] (3) permits the jury that is to decide the defendant's
fate to observe the demeanor of the witness in making his statement, thus
aiding the jury in assessing his credibility.74
69 Trial Court Opinion (“T.C.O.”) at 9.
70 See Commonwealth v. Weeden, 253 A.3d 329, 336 (Pa. Super. Ct. 2021) (“The
report was not altered or amended by any person and no one individual can be considered
its author.”).
71 See T.C.O. at 9; Weeden, 253 A.3d at 336.
72 N.T. at 95, Dec. 4, 2019.
73 Mattox, 156 U.S. at 242.
74 Green, 399 U.S. at 158 (footnote and internal quotation marks omitted).
[J-12-2023] [MO: Todd, C.J.] - 16
By not requiring the Commonwealth to call the analyst as a witness as a
prerequisite to the summary’s admissibility, or by pretending that no such witness exists,
we eschew each of these essential Confrontation Clause protections. Disconcerting as
that may be, the Supreme Court’s Confrontation Clause cases require this Court to look
the other way.
That there exists a witness that was integral to the creation of this documentary
evidence is not the only reason that its reliability should be examined through cross-
examination. The Investigative Lead Summary, and the human analyst’s conclusions
contained therein, are patently unreliable.
Detective Baumgart admitted at trial that ShotSpotter is not a “foolproof” system.75
He conceded that, occasionally, the sounds that ShotSpotter detects are not, in fact,
gunshots, and that “officers have been dispatched to gunshots where there weren’t
gunshots . . . .”76 The detective offered no other explanation for when that happens other
than because the human analyst erroneously interpreted a sound as a gunshot.77
ShotSpotter candidly warns that its Investigative Lead Summary should be used
with caution, as the data may have been altered or may be incomplete. ShotSpotter
expressly limits the recommended use of the summary to “initial investigative purposes
because the shot timing, location, and count could differ once reviewed by a ShotSpotter
Forensic Engineer.”78 The conclusions may have been entirely incorrect, or may have
been subsequently modified. Detective Baumgart did not know whether modification
occurred, and, thus, neither did the jury. Moreover, ShotSpotter advises that the “data
75 N.T. at 96, Dec. 4, 2019.
76 Id.
77 See id.
78 Appellant’s Br. App. D, at 3.
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and conclusions herein should be corroborated with other evidentiary sources such as
recovered shell casings and witness statements.”79 Despite this warning, and despite the
absence of any shell casings to corroborate the summary’s conclusions, it can be
admitted nonetheless, because it is nontestimonial. The defendant is unable to test the
summary’s reliability before the jury.
The purpose of the right to confront witnesses is “to ensure the reliability of the
evidence against a criminal defendant by subjecting it to rigorous testing in the context of
an adversar[ial] proceeding before the trier of fact.”80 Indeed, “the Clause’s ultimate goal
is to ensure reliability of evidence . . . . It commands, not that evidence be reliable, but
that reliability be assessed in a particular manner: by testing in the crucible of cross-
examination.”81 It is difficult, if not impossible, to comprehend how the Confrontation
Clause’s goal of ensuring fair trials is accomplished by applying these core constitutional
principles to testimonial statements while refusing to apply them to other out-of-court
statements that are facially and inherently unreliable, concededly flawed, and
substantially molded by human interpretation, such as the Investigative Lead Summary
at issue today. If an affidavit given under oath to police officers is inadmissible because
it is not put through the rigors of adversarial testing, it is difficult, if not impossible, to justify
exempting ShotSpotter’s summary from this constitutionally mandated process.
One thing is for certain. Even if the division between testimonial and
nontestimonial statements is historically justified, allowing the latter to be admitted without
a corroborating witness on the stand to undergo cross-examination hardly contributes to
79 Id.
80 Craig, 497 U.S. at 845.
81 Crawford, 541 U.S. at 61.
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“the kind of fair trial which is this country’s constitutional goal.”82 To the contrary, it all but
guarantees the opposite. However, unless the Supreme Court of the United States
reverses course in its Confrontation Clause cases, or until this Court untethers Article I,
Section 9 of the Pennsylvania Constitution from the Supreme Court’s jurisprudence and
allows us to examine the question anew under our own charter,83 this inequity shall
continue.
82 Pointer 380 U.S. at 405 (1965).
83 See In re N.C., 105 A.3d 1199, 1210 n.15 (Pa. 2014) (explaining that, because the
language of the Sixth Amendment and Article I, Section 9 are identical, a Confrontation
Clause analysis would be the same under either charter).
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