Gardaí have stepped up armed patrols in several areas of Dublin and Meath in response to the murder of Robbie Lawlor at the weekend.
There are fears Lawlor’s death may trigger a revenge attack on the Dublin criminal’s gangland rivals or their families. Garda sources say there is no intelligence indicating another murder is planned but raised concern about public confrontations or vandalism occurring in the wake of the murder.
Tensions have increased in the Coolock area after videos appeared online at the weekend celebrating Lawlor's murder. On Sunday a close family member was involved in an altercation with the dead man's rivals on a street in the area.
Garda patrols, supported by the Armed Support Unit, have been stepped up in Coolock and Darndale in Dublin and Drogheda in Co Louth.
On Monday family members formally identified the dead man as Lawlor, a father of three.
The 36-year-old, who was closely aligned with a faction in the ongoing Drogheda gang feud and was a suspect in at least three murders, was shot four times in the head with a handgun outside a house in the Ardoyne area of north Belfast.
It is believed he had entered the house before spotting the gunman. He then tried to escape through the front garden.
PSNI and Garda investigators believe he had travelled from Coolock with two other males to enforce a drug debt against a mid-level Belfast drug dealer. They believe he was either set up to be murdered by rivals or that the drug dealer killed him to protect himself.
The men who accompanied Lawlor are from the Limerick area, and have close links to organised crime there. One of them is understood to have links to Limerick gangland figure Wayne McCarthy Dundon, who is serving a life sentence for murder.
Arrested
Three suspects were arrested shortly after the murder which occurred at around noon on Saturday on Etna Drive and a burnt out car was recovered nearby. A fourth man was arrested on Sunday morning.
One man, a 27-year-old, has now been released without charge while three others, aged 33, 30 and 17, remain in police custody.
Det Supt Jason Murphy said on Sunday that he does "not believe that Robbie was in the Ardoyne yesterday by accident".
“I believe he had some reason to be there, and key lines of inquiry for me at this stage are to establish why he was there and what his connection to the address is,” he said.
Security sources say one line of inquiry is that Lawlor was shot dead by the drug dealer who feared he was about to be murdered, while another is that Lawlor was set up by rivals in revenge of previous killings associated with the gang feud which has engulfed Drogheda and Coolock for the past year.
Lawlor, who is originally from Dublin but has an address in Laytown, Co Meath, was the chief suspect behind the murder and dismemberment of 17-year-old Keane Mulready-Woods, whose partial remains were found in Dublin in January. The teenager is believed to have been murdered because of his connections to one of the parties in the Drogheda feud.