Shotspotter vs Vice On Altering Evidence Allegations

Vice alleged gunshot detection provider ShotSpotter has altered evidence as directed by police. ShotSpotter disputes this and, in one of the cases, explained the discrepancies as standard procedure and charged Vice with misunderstanding its methods.

Inside this note, we examine the evidence and responses from both sides and analyze what is most likely correct.

Vice reported that court records, including expert testimony, suggested ShotSpotter altered reports at the behest of police. ShotSpotter has denied altering evidence to coincide with any narrative.

Vice Report

Vice reported that in one case, an alert was initially reclassified from firework to gunshot during the human verification process that ShotSpotter alerts undergo and changed the location months later prior to use in court. Vice added that ShotSpotter "has not allowed any independent testing of its algorithms" and that the prosecution withdrew the ShotSpotter evidence when the defense made a Frye motion (a hearing to determine whether evidence is scientifically accepted) to have ShotSpotter reports disqualified.

ShotSpotter Explains

Vice implied that ShotSpotter’s initial manual reclassification of one noise from a firework to a gunshot was improper, but ShotSpotter was clear that humans verify alerts. It also occurred automatically once the noise was detected, so it does not make sense for ShotSpotter to have modified it on behalf of the police, who had not yet received the alert.

Vice also reported ShotSpotter manually reclassified the location of that alert, implying it was changed by over a mile, but ShotSpotter confirmed to IPVM that the longitude/latitude coordinates show the distance was reclassified by ~23m:

Vice misunderstood how locating gunshot works in ShotSpotter. [...] In the Williams case, the alert and the forensic analyses agreed as to the longitude and latitude to a tolerance of meters. The difference was not “over a mile.” However, when longitude and latitude were converted into a street address—which is what police needed to respond to an incident—the longitude and latitude corresponded to a large park. It has one address that covers a large area.

Vice did not respond to IPVM’s request for a response to ShotSpotter’s statement.

Evidence Withdrawn

ShotSpotter also denied Vice's charges that evidence was withdrawn to avoid having to defend it in court from a Frye motion, and instead says it was withdrawn due to not fitting the prosecution’s case:

The prosecutor’s theory was that the gunshot occurred in the victim’s car. Once ShotSpotter learned of this theory, it approached the prosecutor and informed him that the ShotSpotter evidence could not support this theory. ShotSpotter has long informed the public, prosecutors and police that ShotSpotter cannot detect gunshots that occur in a car or a building. In short, the prosecutor’s theory of the case was inconsistent with the evidence. ShotSpotter so informed the prosecutor. Far from a case of tampering with evidence, ShotSpotter informed the prosecutor that the evidence it had would not support the prosecutor’s theory.

Vice: ShotSpotter “Found” Additional Shots

In two other cases, Vice reported a ShotSpotter expert changed the number of gunshots detected after police asked them to reanalyze the alert prior to criminal proceedings. Vice notes in both cases the changes coincided with the authority's narrative of the crime. ShotSpotter says this occurred due to standard additional analysis:

As opposed to the detect and report service, the forensic service requires a detailed forensic analysis of the gunfire. It provides a more detailed analysis of gunfire. As an example, the immediate detect and report service may or may not report multiple gunshots, the forensic analysis would.

ShotSpotter Denies Any Wrongdoing

ShotSpotter denied that they changed evidence at police request, saying they simply corrected errors during the standard process that occurs prior to use in court.

ShotSpotter forensic evidence is 100% reliable and based entirely on the facts and science. ShotSpotter has never altered the information in a court-admissible detailed forensic report based on fitting a police narrative. [...] The idea that ShotSpotter “alters” or “fabricates” evidence in any way is an outrageous lie and would be a criminal offense. We follow the facts and data for our forensic analysis. Period.

Testing Questions

Vice said the lack of independent testing, including at IPVM's request, calls into question ShotSpotter's overall effect.

At the core of the opposition to ShotSpotter is the lack of empirical evidence that it works—in terms of both its sensor accuracy and the system’s overall effect on gun crime.

The company has not allowed any independent testing of its algorithms, and there’s evidence that the claims it makes in marketing materials about accuracy may not be entirely scientific.

Although ShotSpotter denied altering evidence on behalf of police, these accuracy issues are troubling, especially because of the use of ShotSpotter alerts as evidence in criminal cases.