BALTIMORE (AP) — Baltimore prosecutors on Wednesday announced the arrest of a man in the cold case homicide of an off-duty Washington, D.C., police officer in 2017.

The officer, Sgt. Tony Anthony Mason Jr., was shot to death while sitting in a parked car with a woman he had been dating, according to police. She was also shot but survived.

The case sat unsolved for five years until detectives received a tip in early 2023 that reinvigorated their investigation and led to charges against Dion Thompson, 24, prosecutors said in a news release Wednesday. Thompson, who was 18 at the time of the shooting, is currently serving time in a federal prison on unrelated drug and gun charges.

An attorney representing Thompson in that matter said he isn’t representing him in the murder case, which wasn’t listed yet in online records.

His charging documents in the 2017 shooting don’t include a clear statement of motive and they’re based almost entirely on the account of someone who knew Thompson but didn’t directly witness the crime. The person said Thompson admitted to shooting up a parked car because as he was leaving his friend’s grandmother’s house, he spotted a vehicle whose occupants he didn’t recognize and became paranoid, assuming they “were there to either rob him or retaliate against him for all the robberies he was committing,” according to the charging documents.