The family of murder victim Eugene Carr has offered a large reward for information on the fourth anniversary of his death.
Mr Carr, 73, was stabbed with a hook during a robbery at his County Armagh home in 2015.
He was asleep in bed in the house in Clogharevan Park, Bessbrook, in the early hours of 31 August when three men broke into the house.
A £20,000 reward is being offered by Crimestoppers and Mr Carr's family.
The pensioner was stabbed 15 times and cash was stolen during the break-in.
He died in hospital 11 weeks later.
Det Ch Insp Eamonn Corrigan said the attack was "vicious and unrelenting".
"It has been a difficult investigation, and I have been unable to establish a clear motive as to why this defenceless, elderly man was attacked so brutally," he said.
"I'm aware of rumours as to why this happened... the investigation has found no substance to these rumours.
"These rumours may have been made up by those involved to justify their actions."
A £20,000 reward is being offered to anyone who has any information.
The money comes from both Crimestoppers and Mr Carr's family.
Three of the victim's daughters have given £10,000 towards the reward.
One of his daughters, Patricia, said the family has not recovered from the killing.
"The gaping hole in our lives is made worse by the fact we know his killers are still out there living their lives while ours are ruined," she said.
"We hope £20,000 will be an incentive to people in the community who knows the identity of those who murdered him to come forward.
"Please, please, if you have any information about who murdered our dad, do the right thing and come forward. He deserves justice and to finally rest in peace."