A ShotSpotter device on a light pole surveils the intersection of 87th and Carpenter (photographed in January 2024). Credit: Jim Daley

Since 2018, ShotSpotter has built a network of thousands of gunshot-detection sensors across 12 of Chicago’s 22 police districts. The devices detect loud noises that a computer algorithm and human analysts review to determine if they’re gunshots and dispatch police to scenes of shootings. The technology is controversial: studies have raised questions about its efficacy, and activists who say it harms Black and Brown communities have called on the City to cancel ShotSpotter’s contract for years.

Our six-month investigation combined leaked company emails, public-records requests, interviews, on-the-ground reporting, and data analysis. We found that the Chicago police reported hundreds of missed shootings to ShotSpotter, including a 55-round shooting that left two men critically wounded. We also uncovered ShotSpotter executives’ internal discussions about their inability to repair broken sensors in Chicago and found they were warned repeatedly about electrical code violations. We found ShotSpotter sensors in police districts the City hadn’t previously acknowledged them being in, and revealed that the company has continued collecting gunshot data in cities after contracts were canceled. And we showed how ShotSpotter, CPD, and City Council members worked behind the scenes to try to keep it.

After we published the first part of this series, the Community Commission on Public Safety and Accountability held a public meeting on ShotSpotter. The following week, Mayor Brandon Johnson announced that he would fulfill his campaign promise to not renew ShotSpotter’s contract. At a press conference, the mayor was asked what the deciding factor was in canceling the contract.

“With this particular form of technology, there has been a series of investigations and reports that have indicated that the return on that investment…hasn’t yielded the results it promised,” Johnson said.

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In 2022, two men were critically wounded in a hail of bullets in Back of the Yards. The next day, a Public Safety Administration director complained to a ShotSpotter executive that the company’s senors failed to detect the shooting. Internal company emails show ShotSpotter executives blamed the miss on three downed sensors in the vicinity. The executives didn’t know when the company would be able to repair the downed sensors—and said they could not admit that to the City. Data we obtained from CPD shows the department reported hundreds of missed shootings to ShotSpotter in 2023.


In 2019, the French billboard company JCDecaux asked ShotSpotter to monitor the areas around several electronic billboards it claimed had been shot at in police districts on the far Northwest Side. With CPD’s blessing, ShotSpotter obliged. The company quietly established three small coverage areas around the billboards, which are in neighborhoods that have some of the lowest levels of gun violence in Chicago. Before our investigation, neither the City nor ShotSpotter had publicly acknowledged these neighborhoods had sensors in them.

Several cities, such as Dayton, San Diego, and San Antonio have canceled ShotSpotter contracts, and Mayor Brandon Johnson is attempting to cancel Chicago’s contract as well. We obtained internal company emails that show ShotSpotter kept its sensors online and provided gunshot detection alerts to police departments in cities where its contracts have expired or been canceled.


three: HOW shotspotter made its case

In November 2023, the day before the City Council voted on Mayor Johnson’s 2024 budget, ShotSpotter’s CEO told investors in an earnings call that there was a line item in the budget for acoustic gunshot surveillance technology. But both the CEO and a spokesperson for the mayor denied anyone had given the company any indication the contract would be extended.

After Johnson was elected, ShotSpotter CEO Ralph Clark issued a public statement congratulating him. That same day, Clark sent an email to employees that blamed the company’s share price drop on Johnson’s victory and said executives planned to lobby support for renewing the contract. Emails obtained from the Mayor’s Office reveal how that lobbying effort played out—and show executives met with a mayoral advisor days before the 2024 budget vote in City Council.

After Mayor Johnson announced he wouldn’t renew ShotSpotter’s contract, City Council members launched a bid to force him to keep it in their wards. As part of that effort, they commissioned a CPD report that compared police response times to ShotSpotter and 911 to bolster their case. We obtained the report via a public-records request and revealed that a footnote in it admitted its underlying data was inaccurate. Eight subject-matter experts who reviewed it said it lacked key statistics, and several challenged the accuracy of the response times.


ShotSpotter is suing two employees whom the company alleges stole trade secrets and posted them on Twitter/X. The Weekly broke the news of the lawsuit, reporting on-site from the California courthouse where arguments are being heard.

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