A "guns for hire" gang is being blamed for the weekend murder of Dublin criminal Michael Devoy.
Gardai believe Devoy was shot dead after a €30,000 contract was placed on his head on the orders of a major Irish crime figure, who is currently living overseas.
Devoy was targeted after the crime lord decided he had been the "trigger man" in an attempt to murder convicted heroin dealer Greg Lynch outside a pub in Dublin's north inner city last October.
Lynch was shot in the head, after a gunman opened fire on a crowd attending a 21st birthday party, but survived the attack.
He is linked to associates of the crime lord, who is believed to have ordered the hit on Devoy in retaliation.
Senior garda officers said last night they were sceptical of underworld intelligence indicating he had placed a €100,000 contract on the deaths of three men, including Devoy.
The contract is believed by gardai to have been taken on by a group who have been involved in a series of criminal activities in counties Louth and Meath, as well as on the north side of Dublin, in the past few years.
The gang involves a 40-year-old Dundalk man, who is well known to gardai and is suspected of being responsible for issuing threats to other criminals who refused to hand over a slice of their profits to the group.
The gang uses cover names such as the "criminal action force" or the "united criminal alliance" to claim they carried out attacks.
The "criminal action force" claimed responsibility for the murder of Real IRA Dublin boss Alan Ryan, who was shot dead in September 2012.
Gardai say the shooting of Ryan was organised by a consortium of gang bosses, who had clashed with the dissident republican over his demands for cash from their drug trafficking and armed robberies.
Devoy was aware, along with two others, that his life was at risk and wore a bullet-proof vest.
He had been arrested by gardai last Tuesday with another man as a result of the execution of outstanding warrants against them.
Devoy (41), from Balbutcher Drive, Poppintree, Ballymun, north Dublin, was taken to Portlaoise jail. But his lawyers took an action against the State for alleged delays in serving the warrants and a court ordered his release from jail on Friday.
He was shot in the left side of the head with a handgun on Saturday night and his body was about to be dumped over a wall, leading to a 30ft drop, at Foxhill Road, Bohernabreena, Tallaght, in south county Dublin.
But local detectives, on a routine patrol, disturbed the killers who jumped into a car and fled. Garda gave pursuit but failed to locate the car, described as a silver-coloured hatchback.
When the officers returned to the scene they found Devoy's body. A post-mortem examination was carried out yesterday by Deputy State Pathologist Dr Michael Curtis, who confirmed that he died from gunshot wounds to the head.
Detailed searches of shrubbery and undergrowth around the Foxhill Road continued yesterday as gardai searched for vital forensic clues to the identity of the killers.
Gardai said at least two men were in the silver hatchback car when it sped away from the scene, shortly before 11pm on Saturday.