Andrew Bedford, 27, from Huntingdon, was last seen in Ramsey in Cambridgeshire on 28 September 1990.
Officers reopened the investigation in April and discovered human bones on land off Stocking Fen Road in the town.
Police said new lines had emerged that they were following up after a 25th anniversary appeal prompted a "number of calls".
Cold case detectives think Mr Bedford was killed with a shotgun sometime during the evening at a garage, which no longer exists in Ramsay, called Mongrel Cars.
Mr Bedford was last seen on the evening of 28 September at Factory Bank, off Great Whyte in Ramsey.
A police spokesman said: "The 25th anniversary appeal resulted in a number of calls to police and during the community engagement officers spoke to lots of people in Ramsey.
"The appeal has given us new lines of inquiry which we will follow up."
Three people were arrested in connection with his disappearance but no-one was charged.
In April, police reopened the investigation as a murder inquiry saying they believed he had been shot.
Bones "consistent with being human" were found by scenes of crime officers, forensic scientists and detectives during a 13-day operation in the town in April.
Mr Bedford was last seen wearing overalls, a khaki jumper, jeans and trainers.
He was described as 5ft 8in (1.72m), of medium build with mousey blond, curly, shoulder-length hair and had a number of tattoos.
A man arrested on suspicion of conspiracy to murder remains on bail.
New leads have been uncovered by police trying to solve the murder of a man 25 years ago.