Tracking the sound of crime
NJ.com
By Alex Zdan/The Times
May 31, 2009
TRENTON, NJ -- Homicide detectives talk about the first 48, the crucial two-day period immediately following a murder during which their investigation is most likely to find leads that will solve the case.
But even more vital to a police officer are the moments immediately after a shooting has occurred, when getting to a crime scene as soon as possible can save a life or take the shooter into custody.
"A few seconds could mean a matter of life or death for that victim," said Sgt. Pedro Medina, a spokesman for the city police department. "And the difference between apprehending and not apprehending the suspect."
A system of acoustic sensors known as ShotSpotter, purchased by the city police department with the help of federal funding, is geared to alert police within seconds of a shooting and get cops to the scene more quickly.
"You can actually smell the gunfire," Police Director Irving Bradley Jr. said. "That's how fast you can go there."
Police say not only will they be able to respond more quickly with the aid of ShotSpotter, but they will also respond with more accuracy. ShotSpotter guarantees the system will pinpoint a shooting site to within 75 feet. Cops say this will remove the guesswork that often comes with 911 calls.
"People call the police and they go, 'I just heard gunfire,'" Medina said. But they often can't place the origin of the shots, he added.
"When you fire a gun, it echoes," Medina said. "Where it's coming from, you don't know."
With the new system, arriving units will be directed to where gunfire has been detected.
"ShotSpotter is going to narrow down the area of where you have to look," Medina said. "It's going to put you right in the area the shots are fired."
The system won't eliminate the need to search the vicinity for suspects or witnesses, but it will limit the range of the search.
"That gives you a place to start," Medina said. "Technology is a tool that enhances our ability to be a more efficient police department."
That technology, used by the military in Iraq and Afghanistan, connects the acoustic sensors and cameras to a central communications center. The system begins to register activity within a hundredth of a second of the start of gunfire, said ShotSpotter senior vice president Gregg Rowland.
"When a gunshot is fired, our sensors all have GPS in them and they hear the arrival of that sound," Rowland said.
Calculating the time of arrival and utilizing the GPS, the system identifies the latitude and longitude of the shooting and notifies dispatchers at their consoles in the communications center within five seconds, he said.
ShotSpotter also detects the amount of shots fired and weapons used. A second later, any cameras in the area installed with the system begin rotating to give dispatchers and officers eyes on the scene.
All the data is recorded, and can later be used in court to prosecute the shooter.
"The DAs tell me that when they play the sequence of fire...they say it's an amazing tool to take the jury to the scene of the crime," Rowland said. The servers that process the shooting data are able to filter out background noises, the company says, as well as potential false positives like fireworks or cars backfiring.
"Other noises are always going off," Rowland said. "We've got to be able to pick out the one thing...and be able to detect it under those circumstances."
The sensors are built to be resilient to temperature changes and weather conditions, so police departments can consistently rely on ShotSpotter to function properly, Rowland said.
"The system becomes a mission-critical tool much like their radios or their cars," he said. "They don't want 'em down for a second and we don't want them down for a second."
The company also provides maintenance and updates for the system as required. For Trenton, where Bradley wants three-quarters of the city's 7.6 square miles covered, that would amount to between $213,000 and $285,000 annually.
ShotSpotter's figures indicate the entire system will cost $1.4 million in total. Bradley said he is confident that money outside the initial $200,000 will come from state and federal grants such as the Weed and Seed program from the Department of Justice.
"We always knew there was funding here for this kind of system," Bradley said. "Even before the stimulus money."
"We've been talking about ShotSpotter for a while," Mayor Douglas H. Palmer said. "This is continuing my efforts and the police department's efforts to use technology to reduce crime."
Bradley says the system is well worth its cost.
"Once (criminals) recognize we have that system in place, apprehensions should increase," Bradley said.
Rowland said ShotSpotter has seen 35 to 40 percent reduction of crime on average in the 36 cities that use it, including Oakland, California and Washington, D.C.
Palmer said ShotSpotter will be an effective crime fighting tool.
"It's an effort to try to reduce the amount of people using illegal guns in the city," he said.
A map of the areas ShotSpotter will cover has already been designed, Bradley said. With federal funding to purchase the first part of the system expected by August, the city estimates it will be set up by the end of this year. Bradley said he hopes to have the entire system up and running in a year and a half.
Contact Alex Zdan at azdan@njtimes.com or (609) 989-5705.
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