Another use of the system is when a police officer is involved. The exact locations of each shooter and who shot first can be determined.
In the current discussions about reducing gun violence, the question arises: How can we keep guns out of the hands of felons and mental patients without infringing on the rights of law-abiding citizens? One answer revolves around a better background check for gun purchasers. But with millions of guns already in American closets and gun cabinets, another part of the answer may be in gunshot detection systems, which provide an exact location when a weapon is discharged.
SST Inc. is the company that makes the ShotSpotter gunshot detection system that's in use in many cities around the U.S. On a recent visit to the SST Incident Review Center (IRC), an alert sounded, a screen popped up with a city, a street view of the precise location and a sound graphic. The computer judged it to be an automobile backfire. The dispatcher agreed and tagged it as such. And while 29 U.S. cities monitored by the IRC were quiet at noon on a Tuesday, that is unfortunately not the case at night and on weekends. Thousands of incidents of gunfire have been noted, with specific data on exact location, suspected type of weapon, and more intelligence and guidance for first responders, investigators and crime analysts.
In one incident, 22 different gunshots from three different weapons were fired from the center of a city intersection. In another incident, the system located a sniper on a rooftop who was apprehended smoking a cigarette waiting for the police to leave. His hiding place on the roof was revealed by a big red dot on the SST computer screens.
One California city's shooting report shows a cluster of gunshots recorded on a high school athletic field. When alerted by SST, police discovered the field was where thieves and gang members took stolen firearms at night to test them. Pinpointing the location and the time of day were used by police officers to catch the shooters, confiscate the weapons and get them off the streets.
The system can also be used when a police officer is involved. The exact locations of each shooter and who shot first can be determined. According to SST's James G. Beldock, such information has been used in court, and each incident thus far has corroborated the police officer's version of the shooting.
The difference is dramatic between a 911 call reporting gunshots and a ShotSpotter report. The first difference is that in areas with ShotSpotter installations, the system identifies and locates 80 percent more gunshots than are reported by residents. Residents may be afraid to have a policeman come to their door, they may be accustomed to gunfire, or they may be uncertain if it is a gunshot or someone setting off a firecracker. In any case, the data shows that only 20 percent of gunshots are ever reported by the public.
Another difference is in finding the exact location. Gunshots may be heard up to a half mile or more away, and 911 calls may come from different locations. Where is the shooter or shooters? Are they moving or stationary? Are the firearms semi-automatic? The gunshot detection system can answer all those questions, while 911 callers usually have no idea. And in those cases, officers must circle the reported locations looking for trouble or a body. With a detection system, even the direction of the gunshot can be determined by the strength of the sound as detected by various sensors, as the blast is loudest in the direction the muzzle is pointing.
According to SST's James G. Beldock, following a moving source of gunfire -- as in one drive-by shooting demonstrated in the IRC -- an ambulance should be dispatched to the location of the first shots, but police sent there will arrive with the shooter long gone. The IRC data gives the police the street and direction of travel of the shooter so they can have a better chance at intercepting the perpetrator.
As Rocky Mount, N.C., Police Sergeant Kevin Bern told Government Technology last year, the city's ShotSpotter installation not only directs police to the exact location of a gunshot and aids the collection of evidence, but it also can prevent violence by locating "confidence shots" by gang members planning an attack on another gang, or someone testing out a stolen weapon, as well as "celebratory shots" into the air on holidays.
According to the National Institute of Justice, homicides committed with firearms peaked in 1993 at 17,075, after which the figure steadily fell, leveling off in 1999 at 10,117. So even though in the United States there are 10,000 gunshot deaths per year, there are an estimated 10 times more shots fired -- and following up on those instances may help police officers stop a problem before it starts.
For more on the issue of gun violence, watch for the March issue of Government Technology magazine.