More than five decades after Captain James Tappen Hall was fatally shot after interrupting a burglary, Maryland police have identified and arrested a suspect, they said Wednesday. Larry David Smith, 70, admitted earlier this month to firing at Hall, a Montgomery County sheriff’s deputy moonlighting as a security guard, in 1971. Then 19-years-old, Smith had been carrying stolen property to his getaway car when Hall confronted him. After being shot, the sheriff’s deputy was transported to a hospital and died three days later. Smith was interviewed by detectives in 1973, though there was no indication they considered him a suspect—despite the fact that the young man knew details about the killing that had never been shared with the public. Investigators who revived the case last year zeroed in on Smith, noting his criminal history and that he’d changed his surname in the years following Hall’s death. In a news release, the Montgomery County Police Department noted the deputy’s death is the oldest cold case it has ever cracked.