Gardaí are today continuing to question a man arrested on Monday in relation to the murder of Paul Quinn in Castleblayney in October, 2007.
Mr Quinn (21), from Cullyhanna, Co Armagh, was lured across the Border and beaten to death in farm buildings near Castleblayney on October 20th that year.
A Garda spokesman said a man in his early 30s, who was arrested in Carrickmacross, was still being held at Monaghan Garda station.
The man was arrested under Section 30 of the Offences Against the State Act.