Victim fell foul of drug traffickers before his murder
Gardai believe gangland figure John Wilson, who was shot dead as he walked into his home on Friday, had fallen foul of a west-Dublin gang involved in drug trafficking.
A man in his 30s arrested by detectives hours after the shooting was still being questioned last night.
He is being held in Ballyfermot and can be detained without charge for up to seven days.
Wilson (35), a father of two, had built up a long list of enemies among criminal gangs in the capital and the Real IRA faction led by Alan Ryan, who was murdered earlier last month.
His suspected involvement in a planned shooting of Real IRA sympathisers, whom the attackers believed were in the Players Lounge in Fairview in 2010, suggested the terrorists might have been behind Friday's murder.
But senior officers say that Wilson had become tangled in a row with west-Dublin drug traffickers in recent months and this was more likely the background to the murder.
Wilson, a brother of two jailed hitmen, had collected his eight-year-old daughter from school minutes earlier and dropped her off at a neighbour's house for the afternoon when he was shot.
A masked gunman was lying in wait and followed him into the hallway, shooting Wilson several times in the back.
Wilson knew his life was in danger and had been injured in the knee in a previous attack, while a viable pipebomb was also left under his car.
He had a regular routine, taking his child to and from her school on a daily basis and his attackers had stolen a brown VW Passat estate two days earlier in Celbridge, Co Kildare, for their getaway.
Investigators are hopeful that the car, although burnt out, may yield some clues to the identity of the gunmen and forensic checks on the vehicle continued over the weekend.
It was the third gangland hit in the State in just five days and the 13th so far this year -- more than the 2011 total.
Gardai are hopeful of making progress with their inquiries into the murder of Gerard Eglington (27), who was shot four times as he tried to escape through the kitchen of his home in Portarlington, Co Laois, last Monday morning while his children were in the house.
The other gangland victim, Declan O'Reilly, was gunned down as he walked along Dublin's South Circular Road with his young son, 12 hours after the Portarlington hit.
Gardai are linking his murder to his acquittal in court of the fatal stabbing of thug and bully Derek Glennon in a cell in Mountjoy jail in 2007, when O'Reilly was serving a sentence for road traffic offences.