Mob boss Wayne Dundon and his killer brother have been celebrating the murder of hitman Robbie Lawlor after he was shot dead in Belfast.
Two senior members of the Dundon gang are being questioned by the PSNI over the fatal shooting at the weekend and are suspected of double-crossing the Dublin criminal.
Lawlor (36) was the chief suspect in at least six murders - including the abduction and dismemberment of 17-year-old Keane Mulready-Woods in January - as well as three botched hits.
He was shot dead shortly before midday on Saturday on Etna Drive in the Ardoyne area by a lone gunman.
The Herald has learned that convicted killers Wayne and Dessie Dundon have been openly celebrating the murder behind bars in their Dublin cell.
The pair are being held in the protection area of B Base at Mountjoy, where they are locked up to keep them away from their gangland associates.
Gardai suspect that €50,000 in cash seized from a female associate of the mob on Monday was payment for Lawlor's murder.
"They have been cheering and celebrating the murder since Saturday. They're walking around now with their chests out," a source told the Herald.
"Neither are saying they were involved, of course, but they're happy out going around the jail. They aren't subtle about it either."
Wayne Dundon (41) is serving a life sentence for the murder of innocent businessman Roy Collins in Limerick in 2009.
Dessie Dundon (35) is also serving a life term after he was convicted of involvement in the murder of Kieran Keane in 2003.
Gardai, who are liaising with the PSNI over Lawlor's murder, believe he travelled to Belfast with three Limerick men before being shot dead.
The PSNI are continuing to question these three, who include a 33-year-old senior member of the McCarthy/Dundon gang and his 17-year-old nephew who is also well-known to gardai.
Earlier this week, the Herald revealed how detectives suspect the Dundon associates doubled-crossed Lawlor after travelling to Northern Ireland to collect a drugs debt.
On Monday afternoon, gardai arrested two women and seized €50,000 in cash on the M7 in Co Laois.
The women, aged in their 20s and 30s, were questioned on suspicion of money-laundering before being released without charge yesterday.
It is believed the cash had just been passed from associates of the Maguire gang, which is involved in the deadly Drogheda feud, to an associate of the Dundons as payment for helping in Lawlor's murder.
The Maguire mob had been involved in a bitter battle with the murdered hitman, and are still at war with his associates. The feud has resulted in four murders.
Lawlor was also the suspected gunman when Owen Maguire (36) was shot eight times outside his Drogheda home but survived.