The country's latest gangland victim was murdered after getting involved in a dispute between the Kinahan cartel and their own mob banker.
Noel Kirwan (62) was shot dead in front of his partner outside his home at St Ronan's Drive, west Dublin on Thursday night.
Kirwan was a childhood friend of Gerry Hutch (53), and drove 'The Monk' to the funeral of his brother Eddie Hutch Snr (59) in February.
The Herald can also reveal that a young associate of the murdered man has sworn revenge against his killers.
In the last month, Kirwan attempted to prevent the Kinahan cartel from carrying out an attack on their own gangland banker - who also works for the Hutch mob.
Gardai believe this failed bid to reason with the international crime syndicate is the reason why Kirwan was shot dead.
On November 23, the cartel carried out a shooting on the businessman's home.
Nobody was injured during the gun attack, but gardai believe it was an attempt to seriously harm or kill the gangland banker.
This individual has no previous convictions but is suspected of involvement in the financial aspect of the feuding Hutch and Kinahan gangs.
Following the attack, Noel Kirwan attempted to act as a mediator in a bid to prevent further attacks on his banker pal.
However, the Kinahan cartel were enraged by Kirwan's efforts to protect his associate and hatched a devious plot to murder the 62-year-old.
It has also emerged that Noel Kirwan spent his last hours at the funeral of one of his friends in Finglas. Key to the garda investigation is tracing Kirwan's movements between the funeral and the gun attack in Ronanstown.
Following Thursday's murder, a young associate of Kirwan, distraught by the brutal killing, vowed revenge against the cartel.
In an ironic twist, it can also be revealed that Noel Kirwan was a close friend of James 'Jaws' Byrne (69) - the father of slain Kinahan gangster David Byrne (33).
A source stated that Kirwan and 'Jaws' had attended several weddings together, and were close friends for several years.
Another son of James Byrne, Liam (36), is a leading member of the Kinahan cartel.
Noel Kirwan (62) was gunned down shortly after 5pm on Thursday evening at St Ronan's Drive in Ronanstown, west Dublin. A lone gunman approached Kirwan as he sat in his Ford Mondeo outside his home.
His partner was in the passenger seat at the time and witnessed the shooting.
Several shots were fired at the victim, including three to his head, before the assailant ran to a waiting van, where an accomplice was waiting to act as a getaway driver.
Kirwan knew his life was in danger and had an elaborate CCTV system installed in his west Dublin home after detectives warned him of the threat.
This threat emanated from Kirwan driving Gerry Hutch to his brother Eddie's funeral in February.
It previously emerged that Kirwan's family home in Kilbarrack was targeted by members of the Kinahan cartel in August.
Nicknamed 'Duck Egg', Kirwan had a number of serious brushes with the law and he was previously arrested for firearms offences.
There was shock in Dublin's inner city when it emerged that he had been gunned down.
A former low-level criminal in his younger years, he had turned his back on crime, according to locals.
"He would have grown up with some of the Hutch family, and it is my guess he was murdered because of this. There is no way he should be a target," a source said.
It is understood Kirwan moved to Kilbarrack some years ago and more recently had been living with his partner in Ronanstown.
His father worked in the docks and it is believed Kirwan inherited his father's unusual nickname from him.