Detectives searching for Kevin John Palmer at a disused former pub in Fareham in Hampshire say he was last seen catching a taxi with two other men and they want to speak to the driver.
Detective Superintendent Paul Barton said: "The last known sighting of Mr Palmer was at the Abshot Country Club on the evening of 12th March 1999 when we believe he caught a taxi with two other men back to an address in Bishops Waltham."
He added: "En route it is suspected that Mr Palmer became involved in a fight with the other two passengers in Curbridge and was left there. I am really keen to trace the taxi driver from that night. Please contact detectives from the Operation Arkholme team at Southampton Central police station."