Sinn Féin President Gerry Adams has denied his movement had any involvement in the murder of a 21-year-old County Armagh man.
Paul Quinn, of Cullyhanna, south Armagh, died following a beating at a farm in Tullycoora, near Oram village in County Monaghan, just south of the border.
Two other men injured in the same attack have since been discharged from hospital.
Mr Quinn's family released a short statement saying he had recently been involved in an altercation with "individual members of the IRA".
They alleged he was lured over the border and beaten to death at farm buildings in Castleblayney, County Monaghan, following a dispute with a south Armagh gang with links to the former Provisional IRA.
"Our son courageously and correctly refused to leave. We believe he was abducted by the Provisional movement and brutally beaten to death."
Mr Adams said he believed the attack was linked to fuel smuggling. He urged anyone with information about the killing to give it to the police on both sides of the border.
Mr Adams said if he had "hard information" he would hand it to the PSNI or Gardai police in the 26 Counties.
"There is no republican involvement whatsoever in this man's murder and all of us should be careful that we don't end up playing politics with what is a dreadful, criminal action," he said.
"The people involved are criminals. They need to be brought to justice and it is fairly obvious to me that this is linked to fuel smuggling and to criminal activity."
Cavan-Monaghan Sinn Féin TD Caoimhghin O Caolain condemned the attack, saying he was "deeply shocked" at the "brutality" of the killing.
"Whatever circumstances are behind the attack there can be no justification for this type of violence. I strongly condemn the attack which took place in my own constituency and urge that anyone with information relating to the murder go to the gardai immediately," he said.
Former Sinn Féin councillor Jim McAllister, a neighbour of the victim's family, backed claims that individual republicans associated with the Provisional IRA were to blame for the killing.
Other commentators pointed out that the border area in question -- once known as 'Bandit Country' in the mainstream media -- is overwhelmingly republican and many families in the area would have had strong IRA connections in the past.
Meanwhile, PSNI police chief Hugh Orde has told unionists that there is no evidence to link the murder to the IRA, according to DUP MP Jeffrey Donaldson. The briefing came against a DUP warning that if the IRA was behind Mr Quinn's murder it could collapse the Northern Executive and Assembly.
Mr Paisley jnr, son of the party leader, said the DUP would wait for a definitive account from the PSNI as to who they believed killed Mr Quinn. He said of Mr Adams's comments: "The language in all this certainly helps; it helps considerably. This would not have happened a year ago, let alone 10 years ago."