Gardai said they seized the man in Cavan town early on Sunday morning and brought him to Monaghan Garda station where he is being held under section 30 of the Offences Against the State Act.

He is the twelfth person to be arrested over the brutal murder.

South Armagh trucker Mr Quinn, 21, was attacked last October by a masked nine-strong gang using iron bars.

He was lured across the border to an isolated cattle shed in Monaghan for the beating after he had defied repeated local IRA warnings to leave Northern Ireland.

Since July, 12 people have been arrested in connection with the killing – six in Northern Ireland and six in the Republic.

But no one has yet been charged with the murder.

The horrific killing sparked huge controversy, and paramilitary watchdog the International Monitoring Commission has blamed the attack on former IRA members and their associates in south Armagh.

Police on both sides of the border believe Mr Quinn was beaten after incurring the wrath of the South Armagh Provisionals after getting the better of a senior veteran republican in a fist fight.

Up to 20 republicans and their associates were involved in the incident, including lookouts and drivers, it has been estimated.

Gardai have found few clues despite a thorough forensic examination, but more than 1,200 leads emerged from the major cross-border inquiry.

Then Justice Minister in the Republic Brian Lenihan met Mr Quinn's parents, Stephen and Briege Quinn, to assure them every effort was being made to bring the gang to justice.

An inquest opened briefly in Dundalk in June to issue a death certificate to his grieving family but it was adjourned because of the ongoing investigation.

Mr Quinn died from blunt force trauma as a result of multiple injuries, and he had damage to his brain and lungs.