Pioneering a new way to synthesize crime information, Boston police made nine arrests in the past year by comparing data from two high-tech monitoring systems: Shotspotter, which reports the location of gunfire, and one that identifies any probationers or parolees wearing court-ordered GPS trackers in the area.
Analysts at the Boston Regional Intelligence Center at police headquarters have been cross-checking data from Shotspotter, the acoustic gunfire detection network deployed in violence-plagued areas of the city, with the probation department’s GPS monitoring system in Clinton.
If the GPS shows a parolee or probationer in the area, it can give police a place to start the investigation; statistics show high rates of recidivism among people who have served time in prison. It can also rule out parolees and probationers as suspects if the GPS shows them far from the gunfire. The approach may mark the first such collaborative effort in law enforcement.
“I haven’t heard of it being done anywhere else,” said Dennis Kenney, a professor at the John Jay College of Criminal Justice in New York City, who has studied both systems.
Analysts at the Boston intelligence center do the cross-checking manually, making phone calls and typing information into a computer, but are working on a system that would automatically merge the information and relay any “hits” to investigators in the field.
“It’s a work in progress, and that will start off as a pilot program, obviously with testing to make sure that it works properly,’’ said David Carabin, intelligence center director.
Approximately 1,800 probationers who wear bracelet monitors are living in Boston, with about a third of them convicted of crimes against people. In addition, the state Probation Department monitors approximately 200 parolees in the city who wear the devices.
“This is a great use of technology that already exists, and it gives investigators a heads-up on who may have been in the area,’’ said Paul Fitzgerald, a superintendent in the Boston Police Department who oversees the intelligence center. He declined to specify the nature of the nine arrests, saying they are currently being adjudicated.
While authorities laud the new technology, however, some people see it as a potential threat to civil liberties.
Matthew Segal, the legal director of the American Civil Liberties Union of Massachusetts, said Shotspotter helps police respond more quickly to crime scenes, but the marriage of that tool with any GPS-based tracking system could diminish constitutional rights for a sector of society that already has a reduced expectation of that protection.
“Often when police want to stop and frisk someone, they will use the ‘high crime area’ rationale, and this is another version of that,” Segal said.
Kenney said he is not a “big fan” of Shotspotter because it has been known to mistake loud noises, such as fireworks, for gunfire. However, he said, the Boston police’s new system “is an interesting application, if they do it in a controlled way.”
One problem that could arise from the cross-referencing, he said, is that many of the people wearing GPS monitors live in areas where gunfire is not uncommon.
But authorities say the system can also exonerate people.
“One overlay recently revealed that a person whose name came up during an investigation as the possible shooter couldn’t have done it because he was not in the area,” Fitzgerald said.
The cross-referencing is not a substitute for typical investigatory methods, authorities said, but they justify it by pointing to the high recidivism rates among former convicts. Fitzgerald suggested that it might also have a side benefit of helping authorities find witnesses.
“We are already seeing impressive results from the combined use of these two systems,” said Police Commissioner Edward F. Davis. “Our strong partnership with the Probation Department is providing us with the opportunity to quickly identify possible suspects and get violent offenders off the street.”
The idea of doing the cross-referencing was born on a Saturday morning about a year ago, when Davis met with Ronald P. Corbett Jr., the commissioner of the Probation Department.