Wichita police quietly tested gunshot-detection tech for 2 years. Now they’re ready to expand it.

The Wichita Police Department plans to purchase around 144 gunshot sensors it’s tested since February 2022, officials said during a town hall meeting in June.

Other than a brief mention of it when police talked about failures of the previous gunshot system in February 2023, which was the first time city and elected officials learned police had been testing the technology for more than a year, it was the first time the department spoke publicly about testing the controversial technology.

The gunshot technology being implemented in Wichita has been controversial in other cities, including lawsuits, concerns about police bias and voice detection, and the question of whether or not the system detects gunshots accurately.

Chief Joseph Sullivan, who inherited the Flock Safety’s Raven gunshot sensors from his predecessor, blamed the lack of transparency on a “glitch in communication” by the previous administration.

He said that the department would be more transparent in the future, including about testing products, adding that when the Raven gunshot sensors go live, there will be a dashboard for people to see alerts and outcomes.

“We want you to see and we want to see, is it working, is it not working?” Sullivan said during the June 8 meeting.

Aujanae Bennett, president of the Northeast Millair Neighborhood Association, was one of about 25 people who attended the town hall meeting.

Bennett said she was concerned about the department’s lack of transparency in testing the product without telling anyone. She said that even though Sullivan inherited the shot detection system, his department shouldn’t have taken 18 months to tell the public about it.

Still, she seemed optimistic.

“I’m praying that it works. I believe it does,” Bennett said into the microphone during a question and answer part of the town hall.

Concerns with the technology

Gunshot technology has been dogged by controversy.

A study by the Chicago Office of Inspector General found it adversely impacted officer policing behaviors in areas with high alerts. That study, and one by officials in New York City , also found that the well-known ShotSpotter system more often than not made false alerts of gunshots. Although it’s only supposed to record gunshots, ShotSpotter has also recorded conversations, according to The Standard-Times in Massachusetts and CBS News .

One ongoing lawsuit against the city of Chicago filed by the MacArthur Justice Center at Northwestern University’s law school says officers used the technology to make illegal stops and arrests.

Matthew Guariglia, a senior policy analyst at civil liberties and data security organization Electronic Frontier Foundation, is concerned that the Raven technology promises to record more than just gunshots, making it even more possible to record things like conversations.

“I guess if someone was screaming. I guess it could capture that,” Flock Safety spokesperson Holly Beilin said.

How the detectors work

Wichita police are familiar with Flock Safety, founded in 2017, after testing its license plate readers in 2020 and then adopting them throughout the city. The license plate readers can record vehicle types and license plates and alert police when they capture a potential suspect’s vehicle.

Sullivan, the police chief, said Raven’s gunshot detection accuracy has improved greatly since he first started in November 2022.

Only two officers in the department – Sgt. Brian Safris and Capt. Casey Slaughter – currently get those gunshot alerts.

They don’t respond to them like a 911 call, but instead follow up later to verify gunshots were accurately detected, police said.

According to Safris, the sensors can only pick up gunshots outdoors, and not inside. Three sensors need to detect a gunshot for an alert to go out, he said.

It records audio for five seconds once a gunshot is detected. Safris said if a series of gunshots lasts longer than that, it will result in multiple recordings, which are deleted after 30 days.

There were 324 gunshot alerts last year, he said.

“One thing that was actually kind of shocking to me through my research here was the fact that there are so many incidents that go completely unreported,” Safris said.

Based on Raven alerts where they found evidence but had no 911 report, police said that around 83% of gunshots in the areas being tested were not reported, something Sullivan said he wanted to change.

“As a result of our slow response times and lack of manpower, I understand a lot of people have lost confidence and they hear gunshots and they don’t report it,” Sullivan said. “When they hear those gunshots, they are going to start seeing police show up, as we should, to let them know that this is very important to us, that somebody has been shooting up your neighborhood and we’re going to do our very best to do something about it, and you will see people call again and report those things.”

Police don’t have a set date on when the gunshot sensors will be adopted or how much it will cost to buy and keep them.

“The cost depends on the time of purchase and the size of the covered area,” Capt. Aaron Moses said. “We are still working through exactly what this looks like based on the available data.”

Gunshot sensor locations in Wichita

Police said they plan to use the sensors in areas with the highest incidents of shots being fired.

A Wichita police heat map of crime between January 2019 and January 2024 shows that most gun violence in the city occurred just west of 13th and Grove and around Harry and Oliver.

Moses said they are testing sensors in those areas along with near Harry and Webb. The total coverage area is just under 2 square miles, he said.

Police are currently testing about 77 sensors. The plan is to double that when the department adopts the system. However, that won’t be enough to cover the entire city.

Raven uses about 40 to 55 sensors per square mile, Beilin said. That means the proposed adopted sensors would cover less than 2% of Wichita.

Police said that if gun crime goes down in an area where the technology is being used, they would move it to another area where there’s also high gun crime. Police won’t say exactly where that will be, but said they would give general locations because they do not want them to be stolen or vandalized.

Bennett, the neighborhood association president, said she wants to see the sensors in all quadrants of the city to prevent the over-policing of certain areas.

What do the sensors record

There are concerns about Raven gunshot sensors recording more than gunshots.

“ Raven is not just a gunshot detection device ,” Flock Safety vice president of products Davis Lukens said in an April 2022 promotional video. “It captures things like glass breaking, wheels screeching and even saws for those catalytic converter thefts.”

Beilin, the Flock Safety spokesperson, said screeching tires were added later and that others will be added over time.

Wichita’s sensors have been updated to include the screeching tires, she said.

Safris, the officer, said he didn’t know whether Wichita sensors recorded anything but gunshots and said he hadn’t been alerted for anything else as of the June town hall meeting.

A 2024 report from the New York City Comptroller’s office reviewed eight months of ShotSpotter data between 2022 and 2023 and found that 7,262 alerts, or between 80-92% of alerts, “did not turn out to be confirmed shootings.”

“ShotSpotter is expected to report 90% or more of probable shooting, thus gives them a strong incentive to over-report loud noises that do not turn out to be confirmed shootings,” the report says.

Flock says its gunshot sensors, which launched in the last few years, detect 90% of gunshots.

Sullivan said, early in his roughly 20 months at the helm, the sensors were nowhere near that. However, recently, Raven’s machine learning has improved significantly, enough to adopt it, he said.

Other concerns are about the technology’s impact on police bias and police misuse.

Areas with the highest alerts have a negative impact on officers’ perceptions and interactions with people living there, a 2021 report from Chicago inspector general’s office found on reviewing the city’s use of ShotSpotter.

The report also found the sensors “rarely lead to evidence of a gun-related crime .”

Additionally, Chicago police “intentionally misused ShotSpotter alerts to make scores of illegal stops and arrests,” according to an ongoing lawsuit. In one Chicago case mentioned in the suit, one man sat in jail for a year, with the key evidence being the gunshot detection and video surveillance , before a judge dismissed the case because of insufficient evidence, according to The Associated Press.

Guariglia, the senior policy analyst, said the gunshot technology was “born out of a lack of trust that communities feel for police departments” and doesn’t fix the underlying problem of improving police relationships with different communities.

Sullivan echoed similar words during a news conference in March 2023.

“Until we have the trust of the community, we won’t have the cooperation of the community,” he said. “I could bring all the technology I want to this department, but solving crime, the foundation, always relies on community cooperation, the community reporting crime and reporting what they see and cooperating in prosecutions.”