GaRdai are investigating whether the capital's latest gangland victim was shot dead because he was in a €300,000 cash dispute with a high-profile south Dublin businessman.
'Fat' Andy Connors (45) was shot twice in the head and once in the chest with a handgun in front of his horrified family.
The balaclava-wearing killer entered through an open patio door at the back of his home in Saggart at 11pm and blasted him in the hallway.
Connors - who had attended a wedding in Co Kildare earlier in the day - was a major player in a gang of Traveller thugs who spread a campaign of terror during hundreds of organised burglaries in recent years.
Gardai believe that 'Fat' Andy and his gang had used a smooth talking businessman to launder huge sums of money that the gang had been stealing in nationwide burglaries.
This man even has his own criminal bodyguard to launder their cash through legitimate building projects.
However, it is understood they have now fallen out.
Detectives are probing whether the businessman ordered the killing over a cash dispute.
A senior source told the Herald: "Information has come in that these two individuals who have worked hand-in-hand for years became embroiled in a bitter row around six weeks ago."
The source explained that both of these criminals, who are high-grade targets for specialist garda units, had accused each other of being responsible for a sum of around €300,000 that has gone missing and serious threats were exchanged.
'Fat' Andy's extended traveller gang - who have over 200 members - are the chief targets of the garda's Operation Fiacla.
The gang are the biggest and most prolific involved in a massive burglary spree which netted over €11m worth of cash and possessions from homes in the last six months of 2013.
Another theory being examined by investigating detectives is whether Connors was murdered by the INLA after he refused to hand over extortion cash to the dissident mob when they demanded €50,000 from him.
Sources say that the cash demand was made by a 32-year-old Crumlin man who leads the INLA in Dublin, but Connors told him to "f**k off".
This man is considered "highly dangerous".
Sources also say that gardai have not ruled out that the businessman and the INLA leader may have worked together on the murder.
"This is a very murky situation and that so-called businessman has very active links to dissident Republicans, so it has to be looked at," a source said.
Connors settled a tax bill with the Criminal Assets Bureau for €150,000 in 2004 and had around 30 previous convictions for burglary, theft, weapons and driving offences.
The father-of-six, his wife, four of his children and niece were in the house at Old Pound in Boherboy in Saggart at the time of the savage murder.
Gardaí believe the killer was aided by others, and was brought to and from the scene by at least one accomplice.