Sinn Fein MP Conor Murphy has said he does not believe there was any republican involvement in the death of a man in County Monaghan.
Mr Quinn was found at farm buildings near the village of Oram
The family of Cullyhanna man Paul Quinn, 21, said their son was abducted and beaten by the IRA because he refused to leave the country.
Mr Quinn was found at farm buildings at Tullycoora near Oram just after 1800 BST on Saturday. He died later.
Mr Murphy has disputed the family's claim, calling the attack unjustified.
Mr Quinn's family said he had been recently involved in a dispute with individual members of the IRA.
"Following this he received a threat by a third party ordering him to leave the country," read a statement from the Quinn family.
"Our son courageously and correctly refused to leave.
"We believe that he was abducted by the Provisional movement and brutally beaten to death."
Mr Murphy said his party had been encouraging people in south Armagh to work with the PSNI.
"We have made a very clear statement that that is the way forward in dealing with these things."
He added: "I am confident that republicans who have been assiduously working on that project - to try and develop a proper and accountable policing service - are not engaged in any other type of activity whatsoever."
Gardai are yet to rule out paramilitary involvement
Gardai said it was very early in their investigation and they were keeping an open mind about the reasons for the assault.
A senior detective also said the possibility of paramilitary involvement had not yet been ruled in or out of the investigation.
Independent unionist MEP Jim Allister said there must be no political pressure put on the investigation if the IRA is involved in the man's death.
SDLP assembly member Dominic Bradley said Mr Quinn had been lured to a farm in County Monaghan where he was attacked by a gang.
"There is utter revulsion in the local community at this act," he said.
It is thought at least three others were at the farm who crossed the border back into Northern Ireland.
Two people arrived at the Daisy Hill Hospital in Newry a short time later to be treated for serious injuries.
Fr Kevin Mullan said the family were devastated by the death.
"His family are in a great state of shock," he said.
"The community are very upset and numb at the death of a young person; one that died in such tragic circumstances, so young."