Mystery still surrounds the death of 19-year-old Dean Geary, whose body was found miles from home, near the village of Gartocharn, Dunbartonshire, in the early hours of February 7, 2010, after a night out with friends.
Police Scotland recently announced it was reopening the investigation following a cold case review. Dean's father John Geary, 46, said: "Someone out there must know something that will help us find the closure we need to move forward with our lives.
"If this has been on your conscience for some time, please come forward and do not take this to your grave. You may have thought that it would not help the investigation but please let the police be the judge of that. Whoever you are, I don't care. Please come forward anonymously, if need be, and help us put a close to our grief."
The death was originally treated as suspicious, then it was concluded in May 2010 that Dean, from Alexandria, had died of head injuries after being hit by a vehicle. No charges were brought.
He left the Tattoo night club in Queen Street about 2am and was seen on CCTV in George Square at 2.40am, then seen near a taxi rank on the corner of Renfield Street and Sauchiehall Street at 3.20am. At 5am three motorists saw him walking on the A811 near Gartocharn.