GARDAI say they are shocked by the brutality of the murder of a young man who was repeatedly shot in the head as he lay dying on the ground.
Officers are trying to establish if the savage murder of 21-year-old Dean Johnson was linked to an earlier row.
Mr Johnson's only criminal conviction was for a road traffic offence.
He was shot twice in the body in the Harelawn area of Clondalkin, Dublin, and slumped to the ground.
The gunman then ran toward him and shot him repeatedly in the head.
Gardai said last night that the victim was hit at least six times, while more than 10 shots were fired.
The shooting took place near a pub at Harelawn Green at 12.20am on Saturday.
Mr Johnson's family said last night they believed he was killed in a case of mistaken identity.
They said the intended target, who had been in the victim's company, phoned them to inform them of the shooting.
The family said the man phoned Dean's brother, Andrew, and said: "So sorry what happened your brother. That was meant for me."
However, gardai said it was unlikely that he was the victim of mistaken identity as the gunmen would have had a clear view of him before opening fire and the gang seemed to be aware of his whereabouts.
But they acknowledged that the level of violence involved was unusual if the shooting was the result of a minor row.
Mr Johnson had been arrested by gardai on Friday after officers stopped a vehicle and seized a number of baseball bats and cudgels.
He was believed to have been involved in a confrontation between two rival groups at The Square in Tallaght.
The gunman and two accomplices made off in a black Vauxhall Vectra car, with tinted windows and registration number 99 DL 7997, which was found burnt out shortly afterwards at Collinstown Crescent in Clondalkin, Dublin.
Mr Johnson was known to have been drinking earlier that night and was blocked by security men from entering a pub.
He was walking around the area when he was gunned down. His distraught mother Elizabeth (58) said she spoke to her son on the phone just minutes before he was murdered.
"When I rang him, he just said: 'Ma, don't worry. I'll be home soon'."
Mrs Johnson said she would regularly call Dean when he was out at night.
"Dean worried a lot about me when I had cancer. He was very close to me.
"I worried about him and I'd ring him every day."
She and her husband Larry were asleep when their son, Mark, came into their room to tell them Dean had been shot in the chest.
Mark said he was in his bedroom with the window open when he heard the gunshots.
"It sounded like bang-bang, bang-bang, bang-bang, bang-bang. At first I thought it might be fireworks. My brother Andrew later rang me and told me Dean was after being shot. I started roaring, crying," he said.
His sister Audrey (37) said: "Dean was just in the wrong place at the wrong time."
No arrests have been made and garda investigations are continuing.
Gardai appealed to anybody who was in the Harelawn Green or Collinstown Crescent areas of Clondalkin between midnight on Friday and 1am on Saturday to contact them at Ronanstown station on 1800 6667700, or on the confidential line, 1800 666111.