Murder squad detectives say they have made a DNA breakthrough in the hunt for the killers of an IRA gunman turned informer 15 years ago.
Eamon Collins, 45, was beaten and stabbed beyond recognition on a country road just outside Newry a short distance from his home in a suspected revenge attack for turning supergrass.
He had received repeated death threats from republicans and it is believed Provisional IRA members from south Armagh murdered him.
He was married with four children.
Collins was deliberately struck by a car while out for an early morning walk with his dogs on Doran's Hill before being beaten and stabbed numerous times in the face and head.
Police said they have a DNA profile from the crime scene but issued a renewed appeal for information about the car used in the attack, a white Hyundai Pony, and a hunting knife, part of which was also recovered from the scene.
Detective Inspector Peter Montgomery, of the PSNI's serious crime branch, said: "Eamon Collins had a well-publicised past but he was a husband and a father and his life was taken in the most brutal and barbaric manner.
"We have a DNA profile from the scene so we are not without hope that one of the killer gang will be identified through the course of police inquiries.
"It is 15 years since Eamon Collins was murdered. Much has happened in the intervening years in terms of politics, policing and allegiances. I would ask those with information about Mr Collins' murder, particularly those in the Barcroft estate, to think again about the awfulness of what happened and about his family. It is never too late to come forward."
Collins turned supergrass after being arrested by police in 1985 but relented and retracted his statements under pressure from his family.
He was subsequently charged with five murders and dozens of terrorist offences but was not convicted and returned to live in Newry in the staunchly republican Barcroft Estate.
In 1997, Collins wrote a devastating expose of the IRA, Killing Rage, based on his life as a terrorist.
He described the torture and murder of an undercover British Army officer in 1977 and how his body was disposed of in a meat mincer.
Collins also wrote and featured in numerous articles for national newspapers.
Coroner John Lecky, at the inquest into Collins' death, said his murder was one of the most brutal, horrific and grotesque murders they had encountered.