Court Opinion

ID: 9897056
Source: CourtListenerOpinion
Date Created: 2023-11-14 19:06:23.360369+00
Date Added: 2024-06-11T09:13:09.150017
License: Public Domain

DISTRICT COURT OF APPEAL OF THE STATE OF FLORIDA
                              FOURTH DISTRICT

                              J.A.R., a child,
                                Appellant,

                                      v.

                           STATE OF FLORIDA,
                                Appellee.

                             No. 4D2022-2469

                            [November 8, 2023]

  Appeal from the Circuit Court for the Fifteenth Judicial Circuit, Palm
Beach County; Lisa S. Small, Judge; L.T. Case No. 502021CJ001093AMB.

   Carey Haughwout, Public Defender, and Nancy Jack, Assistant Public
Defender, West Palm Beach, for appellant.

   Ashley Moody, Attorney General, Tallahassee, and Sorraya M. Solages-
Jones, Assistant Attorney General, West Palm Beach, for appellee.

LEVINE, J.

   Appellant appeals the order which withheld an adjudication of
delinquency for unlicensed carrying of a concealed firearm and possession
of a firearm by a minor. Appellant argues that the trial court erred when
it admitted an expert’s testimony regarding “ShotSpotter” technology,
which can detect the sound of gunfire and notify police. Appellant claims
the state failed to present substantial competent evidence that the expert’s
scientific testimony was reliable. We find that the trial court did not err in
admitting the testimony under Daubert and section 90.702. As to the
other issues raised by appellant, we affirm without further comment.

   On September 14, 2021, at 12:43 a.m., a gunshot detection system
known as ShotSpotter alerted to a shot fired at an address in Riviera
Beach. Using real time surveillance cameras, an officer observed two
males—one of whom was appellant—walking from the immediate area of
the alert. No other individuals were in the area. Another officer
immediately responded to the scene and made contact with the two
individuals. The officer observed bulges in appellant’s pockets, which he
believed to be a firearm. The officer asked the individuals if they heard
any gunshots, and appellant stated he did. The officer asked if he could
check them for weapons, and they both agreed. The officer found a firearm
and magazine inside appellant’s pockets.

   Appellant was charged with unlicensed carrying of a concealed firearm
and possession of a firearm by a minor. The ShotSpotter evidence was
used at trial, in part to explain why police responded to the location and
why they made contact with appellant.

   Before the bench trial, appellant moved to exclude expert testimony
regarding ShotSpotter technology as it relates to detecting gunfire, arguing
the testimony was inadmissible under section 90.702 and Daubert. The
state responded that the testimony satisfied section 90.702 and Daubert.

   During a hearing on the motion to exclude, the court heard testimony
from the expert, Collier, a forensic services manager at ShotSpotter, Inc.,
with seven years of experience. Collier had previously testified over 70
times about the ShotSpotter system and had been qualified as an expert
on most occasions. He explained that ShotSpotter is an acoustic gunshot
detection and location system, which uses GPS enabled microphones and
sensors to geolocate detected gunfire. The ShotSpotter system has three
components: sensors, a location server, and an application. The sensors
receive impulse data, which they pass to the location server, which in turn
processes that data to determine the location. That information is then
passed on to a person who reviews the system’s findings and provides a
classification. At that point, the information is published to an application
that runs on an iPad, iPhone, office computer, or mobile data computer.

   Collier stated that ShotSpotter technology is primarily based on two
techniques. The first technique is the “time difference of arrival,” which
measures the time difference that an “impulsive sound” arrives at one or
more sensors. Time difference of arrival is a concept that when sensors
are pinged or capture an impulsive sound, there are different distances
from that impulse. The process of determining where that sound occurred
is measuring that time difference of arrival. The difference in time of
arrival at two points can be plotted onto a map or graph paper.

    The second technique is “multilateration,” which makes use of the time
difference of arrival at three or more listening locations to determine where
the sound originated. It can be illustrated by hyperbolic curves between
the locations that eventually intersect. Multilateration is used in avionics
to determine the location of aircrafts and airports. Its early uses date back
to World War I, when multilateration was used to determine where to
return artillery fire.

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   Collier testified that ShotSpotter is able to accurately determine the
location of gunfire within a 25-meter radius, which is the length of a
basketball court. An independent audit, using data from 2019 and 2020,
confirmed ShotSpotter had an accuracy rate of 97%, with an error rate of
.41%, which ShotSpotter rounded up to .5%.

   Collier testified in more detail as to each of the components of the
ShotSpotter system. A program manager and project team determine the
optimum placement and number of sensors to be installed. A sensor has
the following primary components: a microphone, a CPU that processes
data and stores audio information, a GPS receiver to know where the
sensor is located and to receive time synchronization, and a means of
connecting to the internet via a cellular radio.

   The sensors listen for impulsive sounds, such as a clap, a dog barking,
or jackhammers. If at least three sensors capture a series of impulsive
sounds, the information is passed on to the location server. The location
server runs algorithms that include techniques like multilateration to
determine whether the sound is likely gunfire and whether the location
can be determined with a high degree of confidence. If the answers to
these inquiries are yes, the location and audio clips are passed on to a
reviewer who determines whether the sound is gunfire.

   Collier noted that ShotSpotter has two incident review centers. Each
review is performed within 60 seconds of receipt. The employees who
review the impulsive sounds are trained to determine whether the audio is
gunfire. They consider how far the sound traveled and listen for context
clues, such as tires screeching. If the reviewer believes there is gunfire,
then the information is published. A published incident goes to user
interface, like an iPhone or iPad, where the user receives an alert to view
the incident on the map and play the audio.

   Clocks on the sensors are synchronized through GPS receivers to
satellite time that is accurate to the millisecond. The system is regularly
checked on three levels to confirm it is working. First, each sensor sends
a signal every minute or so to the location server to confirm it is operating.
Second, third party applications that run on the system check to see if a
sensor is available. Third, the customer support team routinely confirms
the sensors are operating.

    Collier testified that the ShotSpotter system is installed in over 100
cities and has been around over 20 years. He further stated that the
company does not release to the public the location of the sensors or what

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the sensors look like for safety reasons, because some are installed on
private residences, and to prevent intentional destruction or damage of the
devices. The two techniques ShotSpotter relies on—multilateration and
time difference of arrival—have been tested and peer reviewed and are
generally accepted in the scientific community.

   Collier performed a post-analysis review to confirm the time, location,
and account of this shooting incident and documented his findings in a
detailed forensic report. Collier testified in detail regarding his forensic
report, which was introduced into evidence. Four sensors were used to
identify a single gunshot fired at 12:43 a.m. on September 14, 2021, at an
address in Riviera Beach. Although only three sensors were needed, the
fourth sensor confirmed the findings of the other three.                The
multilateration process was used to determine the coordinates and to
provide the address to the police.

   The trial court denied the motion to exclude, finding that Collier
qualified as an expert in ShotSpotter technology. The trial court further
found his expert opinion was admissible under Daubert’s three prongs.
First, Collier’s testimony was based on sufficient facts and data. Collier
went through his report in detail, explaining the facts and data upon which
he relied. Second, ShotSpotter’s technology was based upon tested and
accepted principles in the scientific community, that being multilateration
and time difference of arrival. The trial court further found that the
technology had been tested by a third party, albeit commissioned by
ShotSpotter. 1 ShotSpotter had its own internal checks, such as three
levels of ensuring the sensors are working. Third, Collier applied the
principles and methods reliably to the facts of the case. He explained what
data he used and how he applied the multilateration and time difference
of arrival principles. Based on these findings, the trial court overruled
appellant’s Daubert challenge.

    After a bench trial, the trial court withheld adjudication of delinquency
for unlicensed carrying of a concealed firearm and possession of a firearm
by a minor. This appeal follows.

    Appellant argues that the trial court erred in admitting the expert
testimony about the ShotSpotter technology alert for gunfire, claiming that
the expert’s testimony failed to show the technology was scientifically
reliable. Further, appellant claims that the trial court failed to perform its

1 The trial court noted the error rate was determined to be .15%, but Collier
actually testified to an error rate of .5%, which he explained was rounded up from
.41%.

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gatekeeping function under Daubert. The state, in turn, argues that the
trial court did not abuse its discretion in admitting the expert testimony
of the ShotSpotter technology and that the expert’s testimony satisfied
Daubert and section 90.702.

   A trial court’s ruling on the admissibility of expert testimony under
section 90.702, Florida Statutes (2021), is reviewed under the abuse of
discretion standard. Kemp v. State, 280 So. 3d 81, 88 (Fla. 4th DCA 2019).

   Section 90.702 codifies the Daubert standard as follows:

      If scientific, technical, or other specialized knowledge will
      assist the trier of fact in understanding the evidence or in
      determining a fact in issue, a witness qualified as an expert
      by knowledge, skill, experience, training, or education may
      testify about it in the form of an opinion or otherwise, if:

      (1) The testimony is based upon sufficient facts or data;

      (2) The testimony is the product of reliable principles and
      methods; and

      (3) The witness has applied the principles and methods
      reliably to the facts of the case.

   A trial judge, under Daubert, has a gatekeeping role in order to “ensure
that any and all scientific testimony or evidence admitted is not only
relevant, but reliable.” Daubert v. Merrell Dow Pharmaceuticals, Inc., 509
U.S. 579, 589 (1993). When exercising the gatekeeping function, the trial
judge makes “a preliminary assessment of whether the reasoning or
methodology underlying the testimony is scientifically valid and of whether
that reasoning or methodology properly can be applied to the facts in
issue.” Id. at 592-93.

    Some of the relevant factors to be considered when determining the
reliability of expert testimony include the following: (1) whether the theory
or technique can be and has been tested, (2) whether the theory or
technique has been subjected to peer review and publication, (3) the
known or potential rate of error and the existence and maintenance of
standards controlling the technique’s operation, and (4) the general
acceptance in the scientific community. Id. at 593-94. However, it is also
important to note the test of reliability is flexible, and the list of Daubert
factors do not apply to all experts or in every case. Kumho Tire Co. v.
Carmichael, 526 U.S. 137, 141 (1999).

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   We find that the trial court did not abuse its discretion in admitting
Collier’s testimony regarding the ShotSpotter technology. Collier had
seven years’ experience working at ShotSpotter, including working as a
forensic services manager performing forensic reviews of the technology’s
data and documents. Further, Collier had previously testified over 70
times about the ShotSpotter system and had been qualified as an expert
on most occasions. Based on all this background, Collier had been
“qualified as an expert by knowledge, skill, experience, training, or
education.” § 90.702, Fla. Stat. (2021).

   We also find that Collier’s testimony satisfied all three prongs of
Daubert. First, Collier’s testimony was based upon more than sufficient
facts or data. The testimony included details about the ShotSpotter
system’s sensors, location server, and application. Collier testified how
the location of the gunfire was determined by multilateration, which makes
use of the time difference of arrival, at three or more listening locations, to
determine where the sound originated. Finally, Collier, in the hearing,
went step-by-step over his detailed forensic report.

    Second, Collier’s testimony was the product of reliable principles and
methods. Collier testified that the ShotSpotter technology is based on two
different techniques: multilateration and time difference of arrival. He
explained how these techniques worked to locate a sound. Collier testified
that these techniques have been used since World War I and are still used
in avionics. Specifically, the ShotSpotter system has been installed in over
100 cities and has been in existence for around 20 years. Collier stated
that ShotSpotter is able to accurately determine the location of gunfire
within a 25-meter radius. An external audit confirmed that this system
had an error rate of less than half a percent. Finally, ShotSpotter has
three levels of internal checks to ensure sensors are working.

   Third, Collier applied the principles and methods reliably to the facts of
this case. Collier explained the data he used and how he applied the
multilateration and time difference of arrival principles. In this case, four
sensors were used, even though multilateration requires only three
sensors, and the fourth sensor confirmed the findings of the other required
three sensors.

   Appellant argues that the prongs of Daubert were not met. We disagree.
Trial judges “have considerable leeway in deciding in a particular case how
to go about determining whether particular expert testimony is reliable.”
Carmichael, 526 U.S. at 152. All of appellant’s arguments go to the weight
of the evidence, rather than to its admissibility. Appellant objects, for

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example, to Collier’s testimony because he is not an engineer. However,
an “expert is not required to have an in-depth knowledge of all the
algorithms underlying their technological tools—such as hardware and
software—to reliably testify about the outputs of those tools.” Walker v.
State, 308 So. 3d 193, 198 (Fla. 4th DCA 2020) (citation and internal
quotation marks omitted). Thus, Collier could testify to the “outputs” of
the tools, that being the determination of the location of gunfire.

    Finally, we also note that other jurisdictions have determined that
ShotSpotter technology is reliable and consequently have denied pretrial
motions in limine. See State v. Hill, 851 N.W.2d 670, 689-91 (Neb. 2014)
(rejecting argument that ShotSpotter technology was not reliable under
Daubert and affirming denial of pretrial motion in limine); People v. Brewer,
F082631, 2023 WL 3447037, at *12-13 (Cal. Ct. App. May 15, 2023),
review granted (July 26, 2023) (holding the same); see also Leila Lawlor,
Hardware, Heartware, or Nightmare: Smart-City Technology and the
Concomitant Erosion of Privacy, 3 J. Comp. Urb. L. & Pol’y 207, 220 (2019)
(“ShotSpotter recordings and reports are regularly admitted into
evidence.”).

    In summary, we find that the trial court did not err or abuse its
discretion in admitting the testimony regarding the ShotSpotter
technology and determining that it met the Daubert test. As such, we
affirm.

   Affirmed.

GERBER and CONNER, JJ., concur.

                            *        *         *

   Not final until disposition of timely filed motion for rehearing.

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