The New York Police Department is listening for every gunshot in the most dangerous parts of the Bronx and Brooklyn with the rollout of its latest surveillance tool.
More than 300 ShotSpotter sensors have been placed throughout 17 precincts and three public housing bureaus in the neighborhoods with the highest number of gun crimes and victims.
"Other parts of the city are fortunately they don't have that distinction," Bratton told reporters Monday, adding that they will expand the pilot program over time if it's successful.
"But right now…the Bronx and Brooklyn have more than their fair share and more than the majority of shooting and shooting victims," the police commissioner said.
Currently designed as a one-year pilot program with a $1.5 million price tag, ShotSpotter sensors will be able to triangulate gunshots in five zones that measure about three square miles each.
ShotSpotter records street sounds and grabs anything that might register as a gunshot. The data is sent to California-based technicians who verify whether or not the sound was a gunshot.
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Officials said the program has an 80 percent accuracy rate, with technicians trained to filter out other things that can sound like a gunshot, including fireworks and back-firing engines.
A previous $500,000 gunshot detection system the NYPD tried out in 2011 was abandoned when it wasn’t able to accurately determine what were and what were not gunshots.
Bratton admitted the program will mostly only be effective for gunshots out in the open; it can't pick up gunfire inside buildings or from firearms shooting from inside buildings to the outdoors.
Validated data is then returned to the NYPD and linked up to the department’s other surveillance systems. Through ShotSpotter, cops can get a list of the sensors that picked up the gunshot and how far away they are from the scene.
The same system is linked up to city-owned surveillance cameras and other tools like license plate readers, which can then help investigators track down a suspect.
Bratton confirmed that a ShotSpotter sensor was in place when officers Rafael Ramos and Wenjian Liu were murdered by a lone gunman in Brooklyn last December, even if the real-time alert system was not working yet.