Police on both sides of the Border are continuing to question six men in connection with the investigation into the murder of Armagh man Paul Quinn.
The 21-year-old from Cullyhanna was beaten to death in an isolated Co Monaghan barn last October.
The six men were arrested during a planned operation yesterday involving the Garda and members of the PSNI.
Three men – two in their 50s and one in his 20s - from the Crossmaglen and Cullyhanna areas remain in custody in Antrim.
The other three men – aged in their 20s and 30s - are being held at Garda stations in Monaghan and in Carrickmacross under Section 30 of the Offences Against the State Act.
Well-placed local sources said one of the men arrested by the PSNI was a senior IRA figure in south Armagh, who had served time for IRA offences. They said one of the other men was viewed as a "minor to mid-ranking" republican who had "connections to both Sinn Féin and the IRA".