The criminal shot dead in yesterday's bloodbath in Dublin's Regency Hotel was a 34-year-old man from Crumlin.
David Byrne, from Raleigh Square, has been described as one of the capital's most notorious drug dealers and gangland criminals.
A key Dublin-based member of the Christy Kinahan cartel, Byrne had been a target for specialist Garda units for years,
He was suspected of involvement in the importation of dozens of large shipments of drugs and was believed to have been involved in attempting to smuggle rocket launchers into the country.
Byrne had been arrested numerous times by gardaí over the years.
However, he was cleared of firearms charges in relation to a shooting incident connected to the Crumlin/Drimnagh feud in August 2008.
Officers from the Organised Crime Unit arrested Byrne, who was with the convicted murderer Eugene 'The Devil' Cullen after a 20-year-old man was shot in the lower torso in the incident in Ballyfermot.
Byrne was also called to give evidence in the murder trial of his gangland rival Brian Rattigan in February 2009, where he claimed he could not remember anything unusual happening outside Abrakebabra on August 25, 2001, when Rattigan stabbed Declan Gavin to death.
The Dubliner's life of crime ended yesterday when he was shot dead by a man who was dressed as a Garda but armed with an AK-47. He was gunned down in the reception area of the hotel, where more than 20 people - including children - had been.
However, two of his close friends had more luck when they were hit by the hail of bullets.
Sean McGovern (30), who is from Captain's Road in Crumlin, was understood to be in a serious condition in Beaumont Hospital after being shot in the stomach.
Another man, Aaron Bolger (25) from Killinarden in Tallaght, was being treated for his wounds after he was shot in the thigh.
All three men were known to gardaí and were friends with each other.
None of the trio are suspected of being involved in the murder of Gary Hutch, which is being looked at as the main motive for yesterday's chaotic attack.
However, Bolger is understood to have spent a lot of time in Spain in recent years where he is involved with the MGM gym in Marbella, which Daniel Kinahan, son of Christy, also works in with professional boxer Matthew Macklin.
While McGovern has barely any previous criminal convictions, he was a close friend of the murder victim David Byrne and of Byrne's older brother Liam (38) since they were children, according to sources.
McGovern, who was said to be clinging to life yesterday, was involved in a car business with Liam Byrne and has often been spotted in his company.
In March 2012, it emerged that McGovern, Liam Byrne and another cousin of 'Fat' Freddie Thompson, Liam Roe, were arrested in Liverpool and questioned about making death threats, blackmail and possession of housebreaking implements. However, they were never charged.
Roe survived a botched attempt on his life at the Red Cow Hotel last year when the gun jammed. Gardaí believe that murder attempt was carried out by a north inner city gang.
Ireland's Olympic bronze medallist Michael Conlan's older brother, Jamie, was due to be weighed in at the event in the Regency Hotel yesterday but pulled out of his fight after suffering a shoulder injury in training three weeks ago.