Gardaí investigating the fatal shooting at Gormanstown, Co. Meath, have made a number of arrests.
It is understood the victim was a suspected dissident republican who was gunned down in the car park of the Huntsman Pub in Gormanstown.
He was in his late 30s and had an address in Dunleer, in Co Louth – about 30km (19 miles) from the scene of the killing.
The attack happened shortly before 2.30pm this afternoon.
The scene has been preserved for forensics and an incident room has been established at Laytown Garda Station.
The victim of the shooting appeared before the non-jury Special Criminal Court last year accused of membership of the Real IRA.
The suspect was arrested by anti-terror detectives in a wave of raids across Louth, Wexford and Waterford, during which 10 people were detained as firearms, ammunition and bomb-making equipment were recovered.
The man had denied membership of an unlawful organisation but the case against him collapsed because a then recent Supreme Court ruling had rendered the warrant used for his arrest as unconstitutional.
Gardaí are appealing for witnesses and have detained the arrested men under Section 30 of the Offences against the State Act, 1939 at a number of north Dublin Garda stations.
Anyone with information is asked to contact Laytown Garda Station 041-9813320, or the Garda Confidential Line 1800 666 111.