Top prosecutor says ShotSpotter has little impact on gun violence cases as mayor faces pressure to renew contract

A review by the Cook County state’s attorney’s office has found that ShotSpotter, the controversial gunshot-detection system used by the Chicago Police Department, is “an expensive tool” that’s had a minimal effect on prosecuting gun violence cases.

With Mayor Brandon Johnson on the clock to decide whether to renew the ShotSpotter deal he once vowed to end, an internal document obtained by the Sun-Times underscores previous criticism that the technology is ineffective and overly costly.

“ShotSpotter is not making a significant impact on shooting incidents,” the state’s attorney’s office review states, noting that the technology led to arrests in just 1% of more than 12,000 incidents over a roughly five-year span.

Between August 2018 and August 2023, a total of 160,400 ShotSpotter alerts led to just 2,543 arrests, the document states.

Pat Nabong/Sun-Times file photo

Most ShotSpotter-related arrests “are not severe,” the review found. Nearly one-third of those arrests weren’t tied to firearms. And there’s no year that gun violence arrests — like homicide or reckless discharge — accounted for more than 22% of ShotSpotter-related arrests.

Based on the city’s roughly $49 million contract with ShotSpotter, the cost per each arrest was valued at $14,837.96, with the value increasing for more serious arrests and convictions. Each conviction in the most serious cases cost $714,736.83, the review shows.

State’s Attorney Kim Foxx said her office prepared the report to determine whether the technology is helpful and to engage with Johnson’s administration before his decision.

Reflecting on the data, she said the cost is “pretty steep,” and the technology hasn’t gotten as many “trigger pullers” off the street as she’d like.

“The question is, what is the goal of ShotSpotter?” Foxx said in an interview. “If it is to arrest people who have engaged in any type of crime, and the detection of gunshots can get you there, and you can get anybody and everybody, then it is doing that. It is effective in getting anybody and everybody.

“If it’s about detecting people who have been shot or who have pulled triggers, its effectiveness is quite different,” she said.

Ashlee Rezin/Sun-Times

ShotSpotter saves lives, its parent company says

SoundThinking, ShotSpotter’s parent company, said there are “some serious misleading interpretations” in the report.

The company said other factors need to be considered while pointing to the technology’s key purposes: responding to gunfire that’s not typically reported to 911; assisting victims; bolstering officer safety; helping cops collect evidence; building community trust.

During its time in Chicago, SoundThinking said ShotSpotter has been credited with saving more than 125 lives and has led to the recovery of more than 3,000 illegal guns and over 25,000 pieces of evidence.

Asked why so few arrests are linked to the technology in Chicago, the company said shooters “do not typically remain at the scene of a gunfire incident awaiting police response.”

As result, analyzing early arrests or police reports “is not an accurate way to measure ShotSpotter’s effectiveness.”

Sound Thinking said ShotSpotter is critical for the collection of shell casings and digital evidence that offers “a better understanding of key events that are critical to the pursuit of justice.”

“Our solution is designed to assist the department and the community to address gunfire where it occurs,” the company said. “This analysis entirely overlooks the system’s greatest use: public safety and saving lives.”

ShotSpotter ‘just a way of generating harm for most communities’

Johnson vowed to nix the ShotSpotter deal when he ran for mayor, citing the cost and “clear evidence it is unreliable and overly susceptible to human error.”

Although his signature later appeared on a contract extension last June, his administration claimed it was unwittingly attached to paperwork authorizing a $10 million payment approved by former Mayor Lori Lightfoot.

Mayoral spokesman Ronnie Reese wouldn’t answer questions about the document prepared by the state’s attorney’s office or the ShotSpotter deal, noting only that “the future of the contract will be determined” when it expires on Feb. 16.

Anthony Vazquez/Sun-Times

ShotSpotter was previously slammed in a May 2021 report by the MacArthur Justice Center at the Northwestern School of Law, which found that nearly 86% of police deployments to alerts of gunfire prompted no formal reports of any crime.

In another scathing report that August, the city’s Office of the Inspector General concluded the technology rarely leads to investigatory stops or evidence of gun crimes.

Those reports followed the killing of 13-year-old Adam Toledo, whose death at the hands of a Chicago cop in March 2021 led to renewed scrutiny of the ShotSpotter technology.

Officer Eric Stillman responded to a ShotSpotter alert and chased Toledo into an alley in Little Village, firing a shot into the boy’s chest just a split-second after Toledo dropped a gun and raised his hands.

Freddy Martinez, executive director of the police accountability nonprofit Lucy Parsons Labs, said the document prepared by the state’s attorney’s office shows that “nobody except CPD is willing to defend [ShotSpotter’s] use.”

“It also reveals what we’ve long been saying, that police are using this to arrest people … in cases where they would otherwise be left alone. So it’s just a way of generating arrests,” Martinez said. “ShotSpotter, for all of its claims about public safety, is just a way of generating harm for most communities.”

Martinez believes that “political pressure” has led the mayor to take a guarded approach in deciding whether to renew the contract with ShotSpotter.

Alderpersons push top cop to keep ShotSpotter

In a letter last month to Chicago Police Supt. Larry Snelling, a vocal ShotSpotter supporter, 13 City Council members said the technology is “critical to locating victims, giving first responders the opportunity to render swifter aid and locate evidence.”

The alderpersons represent wards in ShotSpotter’s coverage zone, which includes 12 of the city’s 22 police districts. They argued that funding for ShotSpotter was included in the 2024 budget and urged Snelling to “take all steps necessary to ensure that there is no gap in vital services for the residents of Chicago.”

Ashlee Rezin/Sun-Times

The police department didn’t respond to questions.

Snelling previously signed a memorandum of understanding in October that gave the police department access to another SoundThinking product called CrimeTracer, which allows cops to search police data from across the country.

SoundThinking CEO Ralph Clark told investors late last year that he was optimistic the free, six-month pilot would expand into “a mid- or high-six-figure transaction in the latter half of 2024,” according to South Side Weekly.

‘The technology could be fallible,’ Foxx says

Foxx said her office started having internal conversations about ShotSpotter’s effectiveness after prosecutors dropped charges in a murder case that relied on ShotSpotter evidence.

Although no gun was recovered at the scene, Michael Williams was charged with fatally shooting a man he picked up on the South Side amid the unrest in May 2020.

After the shooting, SoundThinking manually reclassified the sound of a firecracker as a gunshot and changed the reported address of the shooting, according to The Associated Press. The company said it was clear that alerts from inside vehicles or buildings weren’t reliable, and the address was changed to match the location where the shots actually pinged.

Frank Main/Sun-Times file

Still, Foxx said that prosecution showed “the technology could be fallible” in cases where “the consequences are dire for the victim and for the accused.”

“We welcome any tool that can assist us in building strong cases that can lead to convictions of violent offenders,” she said. “In this instance, again, what we are seeing is that this is a tool that is far more effective in the prosecution and conviction of those who are not committing … violent gun offenses.”