A renewed appeal for information has been launched by Irish police probing the beating to death of a 21-year-old man in Co Monaghan.
Paul Quinn was murdered 19 years ago on Tuesday.
His family, who have maintained a campaign for justice, believe members of the IRA were responsible, but Sinn Féin has long denied there was republican involvement in the killing.
To date, 23 people have been arrested in connection with the murder – but no-one has ever been charged.
Gardaí have urged anyone with information to help them bring his killers to justice to come forward.
In a statement, a Garda spokesperson said Mr Quinn and a friend were attacked by a gang of between eight to 10 masked men.
They are believed, at around 6pm on October 20, 2007, to have travelled in a car to outbuildings and sheds at Tullyvanus, Castleblayney, Co Monaghan.
On arrival, they were attacked by a gang of masked men, some of whom were armed with weapons.
Gardaí have said Mr Quinn and his friend were tied up by the gang and Mr Quinn was then subjected to a violent and sustained attack.
They said the attackers are believed to have fled the scene in the white coloured van which has never been recovered in the probe which has seen 23 people arrested to date.
“Gardaí continue to seek any information which may assist in identifying and locating it,” they said.
Detective Superintendent Ronan Carey issued an appeal to the people of the Cullyhanna area of south Armagh to come forward if they have any information.
“Today I am again renewing my appeal to you, the local community, because you have the information we need to progress this investigation. I am particularly appealing to the people in the Cullyhanna area of South Armagh,” he said.
“I am appealing to those men who were in the shed and also to friends or family members of these men who know what happened on the 20th of October 2007 and who, since that time, continue to carry the burden of knowing what happened to Paul on their conscience.
“Time has now passed and the nature of relationships may have changed. I appeal to anyone who was afraid to talk to us over the last 19 years to now come forward. Maybe there was a reason you were afraid, but now is the time to come forward and tell us what you know in confidence.
“I appeal to you to contact Gardaí or the PSNI through any of the following phone numbers or the confidential telephone lines anonymously and help us to bring closure to Paul’s parents Breege and Stephen Quinn who continue to suffer the terrible loss of their son Paul.”
Anyone with information can contact Castleblayney Garda Station on 042 974 7900, the Garda Confidential Telephone line on 1800 666 111 or Crimestoppers (Northern Ireland) on 0800 555 111.