Three people were arrested on Thursday in connection with the fatal stabbing of Kevin Walsh in west Dublin in January.
Gardaà were called to an apartment in the Shackleton estate in Lucan at about 3am on January 7th by ambulance personnel who were treating the victim for serious injuries.
The 35-year-old was taken to Connolly Hospital in Blanchardstown and had been expected to survive after having surgery to treat his wounds, but his condition deteriorated rapidly and he died later that night.
While it is suspected that Mr Walsh was assaulted in an apartment in the Shackleton estate, gardaà have not ruled out the possibility that he was attacked elsewhere.
Detectives believe Mr Walsh took a taxi from Allentown, Tallaght, to the Shackleton area in the early hours of Sunday and have not ruled out the possibility that he had been stabbed beforehand.
A property in west Dublin was sealed off and underwent a forensic examination.
Mr Walsh was well known to gardaà and had previously served a number of prison sentences, including for killing a man in a fight when he was a teenager.
In a statement on Thursday night, a spokesman for the Garda said detectives in Crumlin are continuing to investigate the incident.
He said two women aged in their 40s and a man in his 30s were arrested as part of the investigation.
They are currently being detained at a number of Garda Stations in the Dublin region under the provisions of Section 4 of the Criminal Justice Act 1984.
âThis investigation is continuing from an incident room at Crumlin Garda Station under the direction of a senior investigating officer,â he said. âA Garda family liaison officer continues to keep the deceasedâs family informed of developments.â
Gardaà are continuing to appeal to the public for information in relation to this incident.
Mr Walsh, then of Allenton Green, Tallaght, was 16 when he killed James Burke between September 22nd and 26th, 2005 at the Liffey Valley Shopping Centre, Clondalkin. They had gone to a field to drink cans when Mr Burke, who was British, was fatally assaulted.
Mr Walsh was convicted of manslaughter and sentenced to eight years in St Patrickâs Institution, with the final five years suspended.
He had more than 70 previous convictions, including for violent assault, carjacking, possession of an explosive device, robbery, handling stolen property and road traffic offences.