David Anthony Colon, 19, was shot in the head and killed while sitting in his car on Washington Avenue Extension in Hyannis in the early hours of June 19, 2015. The shooting happened about 2:00 a.m. during what authorities described as a marijuana sale that turned violent. Friends drove Colon to Cape Cod Hospital, where he was pronounced dead later that morning.

Barnstable Police and State Police detectives working with the Cape and Islands District Attorney’s Office identified two suspects, 24-year-old Kyle Jeffrey Walker of South Yarmouth and 19-year-old Keven Seme of Brockton. Surveillance footage placed both men in the area at the time of the shooting. A handgun recovered from a nearby front yard bore Seme’s fingerprint and matched the bullet that killed Colon. Three other people who had been in the same hotel room as Walker and Seme were arrested on heroin-trafficking charges.

Anyone with information about David Colon, his movements that night, or the people involved is asked to come forward.