Days after St. Paul reached its 29th homicide of 2019, police Chief Todd Axtell sent Mayor Melvin Carter an e-mail making his case for buying a gunshot detection system called ShotSpotter.

The technology, the chief said, could help officers respond to and investigate shootings faster, “and bring a sense of calm to our neighborhoods, which are on edge due to the rise in gun-related deaths.”

The mayor was skeptical. In his response, he laid out research showing ShotSpotter doesn’t always work — and even when it does, it doesn’t necessarily reduce crime.

“The available data is inconclusive at best,” he wrote.

As St. Paul grapples with a spike in gun violence and a homicide total that’s reached a 25-year high, the city’s mayor and police chief are divided on whether new technology is the answer. While the chief argues gunshot detection software is “a lifeline,” Carter says it’s a “technological toy.” The split between the two leaders reflects disagreement in St. Paul and across the country about whether systems like ShotSpotter actually help reduce gun violence.

About 100 cities worldwide use ShotSpotter, with varying results. In Minneapolis, which has had the technology since 2006, some council members want to expand the network into neighborhoods that have previously gone uncovered. In St. Louis, researchers found that humans were better and cheaper for detecting gunshots.

In St. Paul, law enforcement officials and community leaders advocating for ShotSpotter acknowledge it’s not an end-all solution, but say they still want to see how it works in their city. St. Paul has reached 30 homicides, 27 of which were by gunshot; as of Nov. 18, police have responded to 1,134 calls of shots fired.

“Our homicide investigators, our detectives and officers are working tirelessly on this problem,” a visibly tired and frustrated Axtell said during a recent interview. “They’re absolutely exhausted.”

ShotSpotter claims it can detect and locate 90% of outdoor gunfire within about 80 feet of a crime scene, and that the system works better than 911 calls because people often wait to report, then give an inaccurate location.

Gunshot detection systems are especially helpful at night and in the winter when streets aren’t as busy, said Daniel Lawrence of the Urban Institute. But the technology won’t fix anything on its own, Lawrence said — police officers still need to follow up with witness interviews and evidence collection.

“The gunshot detection alert is just the starting point,” he said.

Minneapolis Police Cmdr. Scott Gerlicher said the technology has not only helped improve response times to shooting scenes, but “enhances” officer safety by providing police with the approximate location where the shots were fired with a “high degree of certainty.” By listening to the audio, investigators can sometimes tell whether more than one gun was fired, and in some cases, whether it was a small- or large-caliber weapon.

Suspected gunfire sounds that ShotSpotter microphones pick up are sent to the company’s headquarters in California, where an analyst listens to the recordings to filter out things like fireworks or cars backfiring. If it’s a gunshot, local police are notified and get a copy of the recording.

Company executives have said they plan to raise the base price of a ShotSpotter system in January from $65,000 per year per square mile to $70,000.

The St. Paul Police Department asked for nearly $250,000 in the 2020 budget for a ShotSpotter pilot program, but Carter did not include it in the budget he proposed in August. After a violent few months — including a September day when three men were fatally shot in separate incidents — Carter on Wednesday asked the council for about $1.7 million more in public safety funding in 2020. The mayor wants to spend money on things like community ambassadors, streetscape improvements and incentives for landlords to rent to people with criminal histories — but not on ShotSpotter.

While some council members lauded the mayor’s long-term public safety approach, Council Member Dai Thao — who’s advocated for a ShotSpotter pilot program — pushed back, finally asking the mayor, “Do you think that my kids are important to you?”

The mayor responded that he “of course” is concerned for the community’s children, “And that’s exactly why pursuing the perception of safety and buying technological toys because they sound like — and because someone told us, or maybe someone e-mailed us — that it’s an effective way to prevent and reduce gun violence in our community, is not enough,” Carter said.

Chauntyll Allen, who was elected to the St. Paul school board this month, said she appreciated Carter’s focus on youth outreach and other community-led efforts to reduce violence. Like the mayor, Allen said she’s not convinced ShotSpotter would reduce gun violence.

Other community members were disappointed. The African-American Leadership Council plans to meet with Carter this week to ask him to reconsider his position on ShotSpotter, said Tyrone Terrill, the group’s president.

Terrill read the report referencing doubts about ShotSpotter’s effectiveness in St. Louis, but believes Minneapolis is a more accurate comparison for St. Paul.

“Nobody can tell me ShotSpotter doesn’t work,” he said. “We want it and we want it now.”

A Star Tribune analysis of Minneapolis police department data shows mixed results. Of approximately 3,700 reported gunfire incidents in Minneapolis throughout 2018, about a third were generated by ShotSpotter activations. Verifying whether those activations resulted from actual gunshots was not always possible.

On Nov. 15, Minneapolis police responded to a ShotSpotter activation in the 2300 block of Ilion Avenue North. The incident was updated as a shooting near a home in the 1600 block of 22nd Avenue N., which is about 215 feet around the corner from the ShotSpotter activation.

According to a search warrant affidavit, police found a car with several bullet holes in the front driver and passenger sides of the vehicle. A trail of blood led to a nearby home where police found three people shot.

In an interview Thursday, Ramsey County Sheriff Bob Fletcher vowed to pursue whether funding for ShotSpotter could be awarded to his office, so he could implement it in St. Paul to the benefit of both agencies.

Local corporations may be willing to help cover operating costs, he said, but declined to specify which companies had expressed interest.

“There’s no indication it’s going to stop,” Fletcher said. “The cold weather is not likely to be much of a deterrent to these kids who insist on retaliating against each other.”