Detectives said the victim, Jason Martin, 41, from Manchester, was wanted by police in Lancashire in connection with a murder. He was fatally stabbed in the chest during a violent melee at a pub in Ballyfermot, west Dublin, between two local criminal gangs.
Gardaí said a range of weapons were used, including knives, broken bottles, broken glasses and even crutches.
More than 20 men were involved in the fight, which took place between 1.30am and 2am on Sunday.
The violence started inside Hannigen’s pub, before spilling out to a plaza and down a set of steps into a car park. The fight was still going on when the gardaí arrived and there was a confrontation between some of the gangs and gardaí.
Four men, all from Ballyfermot, were arrested under the Public Order Act and files are being prepared for the Director of Public Prosecutions.
Mr Martin was found with a fatal stab wound on the steps, and a second man was sitting in the back of a van with a gash to his stomach. Aged in his early 20s and from Ballyfermot, he suffered serious injuries and underwent surgery on Sunday.
While there was initial speculation the fight may have been planned by the gangs, gardaí said this was not the case.
He said the fight could have been sparked by something minor, such as a perceived personal insult.
Some of those involved are understood to have been at the Bernard Dunne boxing fight in the O2 arena.
Gardaí are going through CCTV footage and are taking statements from security and bar staff. Sources said they didn’t expect early arrests.
Meanwhile, a 17-year-old youth was charged yesterday in connection with the fatal stabbing of a man in Blarney, Co Cork, on Saturday.
The teenager appeared before a special sitting of Cork District Court yesterday afternoon.
The teenager, who cannot be named, was charged with intentionally or recklessly causing serious harm to Shannon Ruby at Ard na Gréine, Station Road in Blarney on September 26.
Judge Uinsin MacGruairc remanded the accused in custody to appear again before the District Court on Friday. An application for legal aid was also granted.