The victim of the capital's latest gun murder was riddled with bullets on his mother's doorstep.
Thomas McCarthy (55) was shot at least eight times when he opened the door of his mother's home to a gunman at 11am yesterday at Croftwood Park, Ballyfermot.
Mr McCarthy may have been targeted by a notorious local criminal who feared that he was going to be attacked first, the Herald can reveal.
Gardai are investigating if Mr McCarthy travelled back to the capital from his home in England to "seek retribution" after a 25-year-old local criminal was blamed for assaulting a woman who was well-known to the victim.
"If the theory proves correct then they got to Mr McCarthy first and brutally murdered him at his mother's home," a source said last night.
The 25-year-old criminal has numerous previous convictions, including for knife crimes and reckless driving, has served a number of jail terms and has also been homeless on occasion.
However, gardai are investigating all circumstances around the killing and have not ruled out the possibility that Mr McCarthy was the victim of mistaken identity.
Senior sources told the Herald last night that Mr McCarthy was not known to gardai for involvement in organised crime, but a man well known to him has connections to the gang led by notorious criminal Derek 'Dee Dee' O'Driscoll.
"The deceased man was living in England and he had only been back for just over a week," a senior source said.
"While he is not known to gardai for involvement in organised crime and his motivations for being back here are being examined, he is also close to a Ballyfermot man with connections to the O'Driscoll crew, who have been involved in organised crime for decades.
"Another theory is that it was this individual who was the target and the gunman just let loose on whoever answered the door.
"This was relatively well planned, even down to a lack of CCTV in the area where the cars were burnt out so there is definite local knowledge in whatever theory proves to be true," the source explained.
A senior source said that four shots were discharged at the victim when he answered the door and another four shots were fired at him inside the house as he attempted to move away from the lone gunman who wore a face mask.
Mr McCarthy is understood to have a partner and children living in England.
Gardai yesterday appealed for information in the case and Superintendent Tony Twomey led a briefing at Ballyfermot Garda Station.
He said gardai were interested in finding a blue Ford Fiesta, which was burned out at Le Fanu Drive nearby, and a silver Skoda Octavia, which officers believe drove to Monksfield Walk in Clondalkin and travelled through Park West or the New Nangor Road.
It's believed the lone gunman drove the Fiesta to the shooting and then burnt it out before getting into the Octavia to flee.
"A male abandoned the car in Monksfield Walk and left towards a green area adjacent. We have no further information of travel after that location," Supt Twomey said.
"We are appealing to motorists and pedestrians who may have been in any of those locations between 10.30am and 11.30am and who may have seen anything unusual. We are also appealing for anyone with dashcam phone footage."
Supt Twomey added that although it's early in the investigation it seemed the two vehicles were used by the lone gunman.
"The victim had recently returned to Ireland and we are still trying to establish a motive.
"It's the early stages so there's a lot of information to gather. We are really interested in seeing what the public have seen. There were other people in the house."
The garda confirmed they were members of the man's family.
The area of Croftwood Park where Mr McCarthy was killed is a quiet cul de sac in Cherry Orchard, with a large green area in front of the house he was in when he was targeted.
This means the killer could only get in and out of the estate on the same road.
The house was sealed off yesterday morning as shocked neighbours gathered at their gates.
On the green in front of the house there were goal posts set up for the local children, who played while gardai and detectives discussed the incident beyond the streams of garda tape that stretched across the roadway in front of the house.
Neighbours said they heard shots yesterday morning but did not immediately know where they were coming from.
Those that spoke said they did not see anybody escaping the scene.
"All we saw was the commotion afterwards, gardai and the armed support unit, and the ambulance was there for a while," said one local woman.
A pathologist inspected the scene at the front door of the house where Mr McCarthy was targeted, before moving inside to continue.
Later, in the early afternoon, members of the Garda Technical Bureau arrived to carry out a forensic examination of the scene.
There had been no arrests last night with a major line in the investigation being that the murder was carried out by either the reckless 25-year-old criminal or enemies of the 'Dee Dee' O'Driscoll gang.
Last October more than €250,000 was seized from Derek 'Dee Dee' O'Driscoll (43) and his associate David Reilly (36) as part of a CAB probe which revealed the gangsters were involved in an extortion campaign in which Dublin City Council workers were targeted in a spate of violent crimes.