Gunshots tell a story, if you pay attention
When a "shots fired" call comes in to a police dispatcher, the shooter has often left the scene by the time the police arrive. The officers then must painstakingly investigate and seek evidence to try to determine what happened. The toughest part can be figuring out where a shot came from.
That's where a gunshot detection system (GDS) can help.
The Nassau County Police Department, based in Mineola, N.Y., uses a system from ShotSpotter that relies on multiple carefully placed electronic sensors installed throughout a neighborhood to help pinpoint the exact source of gunfire. It's especially useful in areas where shots are fired frequently and witnesses are scarce or hesitant to talk.
"When we took a look at this, we realized that a portion of our community was disproportionally affected by random gunfire," said deputy commissioner William Flanagan, noting that in some neighborhoods bullets were often shot into the air, into the ground or into buildings, endangering residents. Police wanted to find a way to cut the incidence of random gunfire and turned to the ShotSpotter GDS.
ShotSpotter, based in Mountain View, Calif., offers its systems as subscription-based hosted services, typically charging $40,000 to $60,000 per square mile per year, according to a company representative. The data is available on the computers in patrol cars, Flanagan said, which helps officers get to the scene quickly when shots are fired.
"We looked at this product and installed it in a three-square-mile zone," Flanagan said, noting that the department sought the approval of community residents before doing so. "Once we installed it, we found rates of random gunfire that were astounding to us." Not many people were being hit, but it was clearly a dangerous situation, he said. "What was more bothersome was that we were not getting calls about it," he added. "People weren't calling because it happened so often they were desensitized."
The department uses the gunshot data in conjunction with its own mapping and analytics tools to find out who lives in the areas where the gunfire occurs to see if there are connections. The analytics tools will, for example, indicate if parolees and people on probation are living in a particular neighborhood. "Really what we're doing is looking inside this area and seeing who is doing the shooting. We've gotten to the point today where we can actually do predictive policing," Flanagan said.
Police have made arrests of suspects by getting officers to the scene quickly after shots were recorded by ShotSpotter. The system even helped the police stop a burgeoning gang war before it really took off, Flanagan said. The department reacted to a rise in gunshots in a neighborhood by deploying special teams of officers whose tactics for keeping the peace included using license plate readers to identify suspects.
"As we learned what was happening, things began to drop off," Flanagan said. In 2010, the system recorded 337 gunshot incidents. In 2011, the number of incidents had fallen to 77, an almost 80% decrease.
One reason for the sudden drop-off, said Flanagan, is that the perpetrators realized that the ShotSpotter system was there. Another is that the police acted on the data they were collecting by deploying special patrols, engaging in anti-violence activities and adopting improved intelligence-gathering methods, he added. "[The GDS technology] told us when and where we had problems," he said. "Technology has assisted us in doing that. It's not a panacea. It's a tool in a toolbox."
There have been some rough edges to work out with the technology, Flanagan said. The biggest issue in the past has been getting the system to better differentiate between actual gunshots and other sharp, loud noises, such as vehicle backfire. ShotSpotter has been "very responsive about anything we've asked them to improve," he said. "We needed some more help with background noise, and they took care of that."
So far, the system has been a helpful ally, according to Flanagan. "At a time of diminishing police resources," he noted, "anything that can be used in the fight against gun violence is a positive step."