Police re-examining the loyalist murders of two Catholic workmen want to trace a man who survived a murder attempt in the early 1970s.
The murders being re-examined are those of John Benedict Devine in July 1989 and John Joseph O'Hara in April 1991.
The cases were re-opened after officers heard taped interviews with loyalist paramilitaries for a Boston College history project, the BBC understands.
A detective said details about the early 1970s murder bid were "vague".
Det Insp Neil McGuinness of the Legacy Investigation Branch said despite this, he was confident that some people would know about the "terrifying" attack that happened in the Falls Road area of west Belfast.
"We believe the victim was walking to work early on a Monday morning when he was approached by a group of men in a car," he said.
"One of the culprits got out of the vehicle, held a gun to the man's head and fired it but the gun failed to go off.
"The victim was then hit over the head with the gun before his assailants fled the scene."
The detective also renewed his appeal for information about the murders of Mr Devine and Mr O'Hara.
Mr Devine, 37, was shot dead at his home in Fallswater Street, west Belfast, on 23 July 1989 as he sat in his living room with his 13-year-old son.
On 17 April 1991, Mr O'Hara, a 41-year-old taxi driver, was shot at Dunluce Avenue, south Belfast, as he went to pick up a passenger.
No-one has ever been charged in connection with either murder.
Det Insp McGuinness said: "I would once again urge anyone who was in the area at the time of either of the murders or anyone who has information in relation to the activities of loyalists in the area in the late 80s and early 90s to come forward."