The Boston Police Department's ShotSpotter system actually led officers right to one of the suspects in a Mattapan murder minutes after the victim was shot, but because police didn't find the body until the next day, he was let go - and promptly fled the state.
Freddie Bing, 49, was shot repeatedly on Wilcock Street in Mattapan on the evening of May 13, while he was talking to friends - but apparently none of them realized how seriously he'd been hit, because he walked away, only to collapse in a nearby parking lot, where he bled to death. His body was not discovered until the next morning.
The sound of gunfire was picked up by the ShotSpotter system - which uses sensors on tall poles in high-crime areas to detect gunshots and direct police to their location. Officers responded immediately to Wilcock Street, where people told them the shots came from a black mini-van. Police say officers soon found an empty black mini-van with a still warm hood - along with several shell casings around the vehicle. Just then, police say, officers noticed another vehicle peeling out of the area - after first backing into another car. They stopped the car and, on questioning and frisking the four men inside, found a key fob that turned out to be from the mini van.
One of the four men in the car was Abiona Justice Sharpe, 20, of Revere. Officers radioed in his name and found he was wanted on a parole violation in Chelsea. He was put under arrest. Also arrested that night was another occupant of the car: Reade Armstrong, 19, charged with unlawful possession of ammunition.
But with no reports of shot people - let alone a body - police did not charge Sharpe with a more serious offense. The Suffolk County District Attorney's office, says Sharpe cleared up the parole issue and, with no other charges against him, walked out a free man.
Police say they eventually linked Sharpe to the murder and tracked him to a New Jersey apartment, where police and US marshals arrested him on Tuesday, after digging him out of a pile of laundry in a closet. Damante Burrell, 16, was indicted earlier this month on a charge of first-degree murder for Bing's death.
Armstrong has not been charged in connection with Bing's murder. He is due back in court on Sept. 9 on the ammunition-possession charge, the DA's office says.