The killing of John Berney, 29, in front of his partner in his bedroom, yards from his two children, is the fourth gun murder this year.
Originally from Ballyfermot, Mr Berney was known to gardaí and had a history of violent offences, including assault on gardaí.
On Thursday night at about 10.30pm, he returned to his home on Castlelyon Drive, Newcastle, west Dublin, after he was out socialising with his friend and neighbour Stephen Barry.
Moments later, the killer entered the house.
The masked man went upstairs and shot Mr Berney a number of times in front of his partner.
While leaving, the killer shot the male friend in the neck.
Both children, Tyrell, 3, and John, 1, were unharmed as was their mother and Mr Berney’s partner, Karen.
A Garda forensic team examined the house yesterday and a pathologist examined Mr Berney’s body.
Clondalkin Superintendent John Quirke described the attack: “One male entered the house. There was an altercation upstairs in the bedroom. A number of shots were fired.”
Supt Quirke said the victim “would have been known to gardaí but not in any serious manner”.
Gardaí said the investigation was at an early stage. A burnt-out vehicle was found near the scene at Glebe, in Newcastle, in which a gun was found.
Stephen Barry, who gardaí reportedly said was lucky to be alive, was recovering in St James’s Hospital last night.
Gardaí were not ruling out a gangland link in the killing of Mr Berney but said it was too early to sayif the killer had an accomplice.
While Mr Berney was known to gardaí in south and west Dublin, most of his offences were minor. He had several convictions for being drunk and disorderly, threatening and abusive behaviour and violence including assault and obstruction of a garda.
In 2001, he spent 18 months in prison and most recently, last year, was again convicted for threatening and abusive behaviour. Reports he was jailed for possession of a firearm, were unconfirmed last night.
It was also reported yesterday that Mr Berney knew his life was in danger and had moved to the west Dublin estate from his home area of Ballyfermot in the last year after being linked with at least two shootings.
Gardaí expect to formally interview his partner Karen today. They have appealed for anyone who had seen any suspicious activity around the west Dublin village on Thursday night to ring them on 01-6667600.
* Convicted robber David Lynch, 39, shot dead in Sligo on January 5 after reportedly crossing a Northern gang.
* Andrew Burns, 27, from Strabane, found shot dead outside a chapel at Doneyloop, Donegal. Dissident republicans are being linked to the death.
* Darren Guerrine, 21, killed with a shotgun blast to the back of his head at the Grand Canal, Bluebell, Dublin. He may have crossed drug dealers.