CHICAGO (WLS) -- Chicago police are using high-tech equipment to try and fight crime in the city.
Critics say the system, known as ShotSpotter, doesn't lead to enough crimes being solved.
In fact, the city's own inspector general's report found less than 10% of ShotSpotter alerts were linked to gun crimes.
However, police said they do help and point to a high-profile crime they credit to being solved quickly, thanks to technology.
A murder in broad daylight shocked the city after a 71-year-old grandfather was shot to death in the middle of the day in Chinatown last month.
Within seconds of the crime, Chicago police received a ShotSpotter alert.
ShotSpotters listen for the sound of gunfire, then send alerts to officers with specific locations.
That alert came into the Strategic Decision Support Center at the 9th District police headquarters.
An officer then looked at city-operated video cameras near the scene of the crime.
Investigators said witnesses helped identify the suspect's car with the help of a license plate reader, which is another piece of technology they use.
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The combination of technologies helped police track down 23-year-old Alphonso Joyner's car about an hour later on the Dan Ryan Expressway.
Joyner is now charged with the murder of Woom Sing Tse. He's pleaded not guilty.
"We stopped him without incident on the expressway, made an arrest [and recovered the gun, so it really highlighted how the whole system works," said Commander Don Jerome with the Chicago Police Department.
Jerome said he was skeptical when the department first opened this Strategic Decision Support Center four years ago. Eyewitness News was recently given exclusive access to the room in an effort to show how it works.
Jerome said despite his initial hesitation, he's now a supporter.
"I've seen success stories almost every day, so I'm convinced," he said.
In a recorded ShotSpotter incident from last week, police said they were able to react quickly enough to find the victim still alive in his car, along with shell casings from two weapons.
"We've seen the benefit. How positive an impact it has on catching criminals, tampering down the violence that plagues our communities," Alderman Raymond Lopez, 15th Ward, said.
ShotSpotter covers Lopez's ward and much of the city.
Every police district in the city now has a room with an officer and civilians keeping close watch, but the technology has plenty of critics.
Last year, the city's inspector general found just 9.1% of the more than 50,000 ShotSpotter alerts were linked to gun-related crimes.
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At the time, Deputy Inspector General Deborah Witzburg wrote ShotSpotter "... should be able to demonstrate the benefit of its use in combatting violent crime. The data we analyzed plainly doesn't do that."
The company responded to questions raised about that OIG report saying, "The Chicago Police Department continually describes ShotSpotter as an important part of their operations. The OIG report did not specifically suggest that ShotSpotter alerts are not indicative of actual gunfire whether or not a police report is filed or physical evidence is recovered. It is important to note that traditional 911 calls for service from community members during this same time period resulted in a police report or evidence found in only 16 percent of incidents, no better than ShotSpotter alerts at 17 percent, and there is universal agreement about the value of the 911 system. ShotSpotter's accuracy has been independently audited at 97 percent based on feedback from more than 120 customers. We would defer to the Chicago Police Department to respond to the value the department gets from being able to precisely respond to criminal incidents of gunfire. We work very closely with our agency customers to ensure they get maximum value out of our service."
"ShotSpotter doesn't reduce or prevent gunshots. It is a response after violence has occurred," said Alyx Woodward, with Campaign to Cancel ShotSpotter.
The Campaign to Cancel ShotSpotter has held demonstrations in an effort to convince the city to cancel its contract with ShotSpotter. They said ShotSpotter is concentrated in Black and LatinX neighborhoods.
"It's the new stop and frisk policy here in Chicago," said Jose Manuel Almanza Jr., with the Stop ShotSpotter Coalition.
A spokesperson for ShotSpotter said, "Coverage areas are determined by police department customers analyzing historical gunfire and homicide data to identify areas most in need of gunshot detection. ShotSpotter believes that all residents who live in communities experiencing persistent gunfire deserve a rapid police response, which gunshot detection enables regardless of race or geographic location."
The number of alerts from ShotSpotter equipment is on the rise. According to city data, alerts were up 39% in 2021. So far this year, they're up 43% compared to the same time last year.
Critics said the millions of dollars the city is spending on the its contract with ShotSpotter would be better spent on community programs to prevent violence.
Lopez agrees about the need for more neighborhood programs, in addition to the technology.
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"This is a tool that allows us to bring people to justice and provide closure for victims," he said.
The city's multi-million dollar contract with ShotSpotter now runs until August of 2023. Opponents, however, said they plan to continue lobbying the city to cancel the contract early.
"ShotSpotter has been in operation for 25 years, serves more than 120 cities, and has earned trust and high renewal rates from many police departments because the system is effective in helping to save lives, capture critical evidence, and make communities safer. We remain committed to our work in Chicago and look forward to helping CPD achieve as much operational value from ShotSpotter as possible," Shotspotter said.