Gardaí in west Dublin have increased high visibility patrols in anticipation of a new round of gangland feuding following the city's latest murder early on Saturday morning.
The killing was the fifth fatal shooting during April.
Detectives investigating the murder of Andrew Glennon believe his associates may seek revenge on those who ambushed the 30-year-old at a housing estate near Clonee village on Saturday.
Glennon was a known drug dealer and was a suspect in a number of gun attacks in recent years, including at least one murder. Gardaí are now trying to establish if he had become involved in any recent disputes that might have led to his murder.
However, sources last night said that given his heavy involvement in drug-dealing and gun crime he would have made many enemies. Glennon had in recent years been an arch enemy of the notorious Blanchardstown-based Westies gang. He was originally a member of the gang in the late 1990s.
However, he fell out with the gang's leaders, Shane Coates and Stephen Sugg, both of whom are now missing, feared dead, in Alicante, Spain.
Coates is believed to have attacked a relative of Glennon's, leaving his face badly scarred. The fall-out over this attack, along with intense rivalry over west Dublin drug-dealing territories, culminated in August 2003 with the murder of Bernard Sugg, a brother of Stephen Sugg.
Glennon was believed to have been one of three men who gunned down Sugg in the Brookwood Inn, Corduff.
The killers struck as Sugg (23) sat drinking with friends in the crowded pub one Sunday evening.
Gardaí expected an intense period of blood-letting but Sugg's brother and Coates moved to Spain shortly afterwards. They went missing in February 2004 and have not been heard of since.
Glennon was originally from Fortlawn Drive, Clonsilla, but had been living with his partner and young children at Huntstown Wood, a housing estate near Clonee village.
It was here that he was gunned down by a gang of four men just before 4.25am.
Gardaí are working on a theory that in the early hours of Saturday Glennon had gone for a pre-arranged meeting at Bramblefield Court, adjoining Huntstown Wood.
As he made his way to the meeting point the gang opened fire on him. Initially he was not wounded and he ran back to his Mazda car.
He managed to get in but as he attempted to start it his four attackers caught up with him. At least one of the four opened fire on him, wounding Glennon several times in the upper body. The gang then fled.
Glennon did not die instantly and managed to drive his car a short distance. However, he passed out behind the wheel and his car mounted a grass verge and came to a halt. He was taken to James Connolly Memorial Hospital where he was pronounced dead.
His death was the fifth gangland killing in April, making it one of the bloodiest periods in recent years. None of the five killings is linked.
Gardaí believe the four men who killed Glennon were all wearing dark clothing and hats or balaclavas.
Members of the Garda Technical Bureau yesterday carried out an examination of the crime scene. Anybody with information is asked to contact Blanchardstown Garda station at (01) 666 7000.
A Limerick man was recovering in hospital last night after he was shot in the back at a bonfire in a housing estate in the city early yesterday morning.
The victim - who is in his early 30s - suffered pellet wounds to his shoulder after he was hit by a man armed with a shotgun.
The shooting happened shortly after 1am in Sarsfield Gardens, Moyross. A 22-year-old man was arrested later and was being questioned last night.
