Minneapolis police are seeking to expand ShotSpotter. Skeptics want proof it works.

For nearly two decades, Minneapolis has relied on ShotSpotter to pinpoint where firearms are discharged in the city’s most vulnerable communities, long plagued by the highest rates of gun violence.

Law enforcement credits the roughly 7-mile network of acoustic sensors with slashing response times, helping investigators collect ballistics evidence and track down suspects who would otherwise have escaped.

Now, city officials are seeking to expand its reach to broader swaths of the city’s south side, including the Whittier and LynLake neighborhoods, where violent crime trends have shifted since 2020. City Council members will be asked to approve a three-year contract extension with SoundThinking, the Fremont, Calif.-based tech company that developed ShotSpotter, at a cost of roughly $963,000.

The new agreement would provide 2 extra miles of coverage in the city — at a time when police staffing remains at historic lows and most gunfire metrics still hover above pre-pandemic levels.

However, ShotSpotter has become controversial in recent years as concerns mounted about potential civil liberties violations involving the surveillance equipment. Critics claim the system is unreliable, does not reduce crime or improve clearance rates, and leads to discriminatory policing of minority residents.

Seattle, Cleveland and Boston have each debated its efficacy. Portland, Ore., ultimately chose to invest in alternative measures. Chicago moved to decommission it later this fall. And New York City must decide before December whether to maintain its gunshot detection system.

St. Paul once considered investing in the program amid a violent stretch in 2019, but Mayor Melvin Carter ultimately rejected the idea, dismissing the product as a “technological toy.”

In Minneapolis, some City Council members want proof it’s worth the investment.

Council Member Robin Wonsley urged staff to commission the first independent evaluation of ShotSpotter since it came to the city. Elected officials require more comprehensive data on the service and its broader impact here, she said, before they can justify renewing or expanding the contract.

“We want to be thoughtful, especially as we go into some very challenging fiscal years ahead, that if we’re spending money on public safety tools they are actually giving our residents meaningful results,” she said. “Not feelings. But actual, quantifiable results.”

In Minneapolis, an examination of 4,100 police responses to ShotSpotter activations throughout 2022 shows about 70% with dispositions indicating police didn’t encounter anything – no victims, shell casings or physical evidence of a shooting – upon arrival, according to a Star Tribune analysis of 911 dispatch data.

Yet, police officials caution, that doesn’t mean a shooting didn’t occur. They reject allegations that alerts are sending officers chasing false reports.

“We would know nothing about the prevalence of automatic gunfire if not for this technology,” said Minneapolis Police Chief Brian O’Hara, who also used the ShotSpotter system when he was public safety director in Newark, N.J. In 2022, a rapid-fire activation on Webber Parkway helped Minneapolis police nab a man testing auto sears, small devices that can turn handguns fully automatic. Similar detections significantly decreased while the man was incarcerated, O’Hara said, because he was probably a street distributor.

The sound echoed through the neighborhood, reaching the gridiron where Minneapolis North High football players worked out in the summer heat two years ago.

Twenty-one staccato pops sent the teens to the ground, covering their heads.

“You would’ve thought the shots were a block away,” recalled Fourth Precinct Inspector Charlie Adams, a veteran police officer who serves as the defensive coordinator for his alma mater.

A ShotSpotter alert on Adams’ phone notified him that the shooting was across Interstate 94 — nearly a mile away. They could safely resume practice.

Minneapolis implemented ShotSpotter in late 2006, when the city faced a 35% spike in violent crime. Coffee can-sized sensors were strategically placed in hot spots throughout the Phillips and Central neighborhoods under a pilot program backed by the American Indian community. It later expanded to the North Side, where dozens of microphones triangulated the origin of gunshots and instantly alerted police, who now had a precise address to respond to rather than flooding a broader area and searching for signs of a shooting.

Triggered by loud percussive sounds, the surveillance network captures audio clearly enough to determine how many rounds were fired and whether there were multiple shooters. ShotSpotter does not, however, purport to reduce overall gun violence.

Although the exact locations of microphones are kept secret from the public, data leaked from SoundThinking in February revealed that thousands of global sensors are perched atop schools, hospitals, billboards, government buildings and public housing complexes. In Minneapolis, one of the earliest sensors was placed on a North Side church — with permission from the pastor and his congregation.

Suspected gunfire sounds that ShotSpotter sensors pick up are sent to the company’s headquarters in California or their incident review center in Washington, D.C., where a human analyst listens to the recordings to filter out ambient noise, like fireworks. If it’s confirmed as a gunshot, local police are notified and receive a copy of the audio file within about 60 seconds.

Today, more than 170 cities and towns use ShotSpotter, although Minneapolis remains the sole customer in Minnesota.

During the height of COVID, President Joe Biden declared that cities could spend a portion of their American Rescue Plan Act dollars to combat a troubling rise in gun violence. Many used that federal funding to pay for ShotSpotter.

But a growing body of research questioning the system’s reliability intensified scrutiny by activists and academics when those contract renewals came before local government bodies.

In 2021, Chicago’s Office of Inspector General released a critical report revealing that less than 10% of the city’s 50,000 ShotSpotter alerts resulted in police finding evidence of a gun crime. Mayor Brandon Johnson, who campaigned on a promise to scrap the technology, accused it of playing a “pivotal role” in the police killing of 13-year-old Adam Toledo.

“It’s creating a significant resource drain,” said Abdul Nasser Rad, managing director of research at Campaign Zero, a nonprofit dedicated to ending police violence. The technology doesn’t improve public safety outcomes or affect case clearance rates, he argued.

Earlier this year, an audit by the New York City Comptroller found that ShotSpotter sent officers chasing hundreds of nonexistent shots and failed to detect more than 200 real incidents of gunfire in 2022 around Manhattan.

Thomas Chittum, senior vice president of forensic services at SoundThinking, dismissed those reports as both politically motivated and “deeply flawed.”

“Even if it was accurate, that still represents thousands of incidents that police may not have known about but for ShotSpotter — victims who would not have received aid but for ShotSpotter,” said Chittum, former second in command at the Bureau of Alcohol, Tobacco, Firearms and Explosives. “Their rush to try and cancel ShotSpotter, should they be successful, is likely to lead to more gun-related deaths.”

Other studies accused ShotSpotter of perpetuating racial injustice. A recent analysis of ShotSpotter activations and U.S. Census data by Alexander Lindenfelser, a University of Minnesota law student and clerk at the Legal Rights Center, found that Black and Native residents in Minneapolis were 3.3 times more likely to live in areas with sensors than white residents.

The frequency of such activations can inflate recorded gunfire incidents in a given neighborhood, Lindenfelser argued, heightening perceptions of danger.

“Police interactions when responding to a ShotSpotter activation have the potential to escalate in ways that damage community trust,” he said in March while presenting his research to a City Council committee. He urged the council to cancel its ShotSpotter contract and invest in other “effective and restorative public safety programs.”

Inspector Adams, who listened from the gallery that day, rebuffed the argument in an interview.

“Death itself has an adverse effect on Black communities,” he said, noting that the vast majority of the city’s homicide victims each year are people of color. “I want to have [sensors] on every corner, if I can.”

In neighborhoods where gunfire has become normal background noise and citizens are less inclined to report it, supporters say ShotSpotter has undoubtedly saved lives.

Lynne Crockett often listens to the police scanner and frequently hears dispatch deploy officers based on activations. It comforts her knowing that Minneapolis has that additional resource.

“I believe the city wastes a lot of money on a lot of things, but I don’t think ShotSpotter is one of them,” said Crockett, a lifelong North Sider and a retired community liaison worker at Minneapolis Public Schools. “I don’t want to see it go away.”

Minneapolis data shows at least a fifth of shooting and murder cases in the Fourth and Third Precincts since 2019 involved police responses to ShotSpotter activations. In areas covered by ShotSpotter, officers spend between 22 and 30 minutes on site, compared to about 44 minutes in northeast Minneapolis, where there are no sensors.

Police say ShotSpotter data helped prove the location of the man who killed 9-year-old Trinity Ottoson-Smith while she was jumping on a trampoline at a birthday party in May 2021. He was later convicted of murder and sentenced to 37½ years in prison.

But roughly 30% of all murders still occur outside of the city’s current ShotSpotter coverage area, so police want to add sensors where crime trends have shifted in recent years. The Whittier neighborhood, for example, has seen a gradual escalation in gunshot victims since 2020, and leads the city in shootings so far this year with 21. Maps reviewed by the Star Tribune show a proposal to significantly expand sensors into stretches of Loring Park and Uptown.

Existing microphones continue to deploy officers to the areas where they were first commissioned nearly two decades ago.

In mid-February, Fourth Precinct officers responded to a ShotSpotter activation on West Broadway near Emerson Avenue N. and found 47-year-old Samuel Yeager Jr. mortally wounded in the street. Despite lifesaving attempts, he died at the scene.

No one ever called 911.