Detectives investigating the feud murders of Eddie Hutch and Michael Barr in Dublin's north inner city have seized a handgun and ammunition thanks to information received during the probe.
Officers from Mountjoy Garda Station arrested a 28-year-old man after the deadly weapon was found in the garden of a house in Ballymun.
The weapon and large quantity of ammunition is linked to the notorious local gang nicknamed the 'New INLA'.
Details of last Friday's top secret operation have only emerged now and the Herald has learnt the arrested man was released without charge over the weekend.
Sources confirmed the firearm seized by officers was not believed to have been used in any of the five murders in the bitter Hutch/Kinahan feud.
"Gardai investigating this feud received specific information, which led to last week's searches," a source said.
"However, the crime grouping targeted in this operation is not believed to be a participant in the feud.
"It is always welcome to get firearms and ammunition off the streets," the source said.
The funeral of the feud's latest victim, New IRA member and father-of-five Michael Barr (36), is due to take place this morning in Strabane, Co Tyrone.
Meanwhile, gardai are continuing to mount operations against the so-called 'New INLA'.
Last month, the Herald revealed the new gang that was involved in a crime summit meeting at the Regency Hotel in February fled the area in a hurry after getting "spooked" by a garda surveillance team who were monitoring their meeting.
Sources said the gang was also believed to be behind two murder attempts against Limerick criminal Sean 'Cowboy' Hanley last year.
One of the senior gang members was suspected of being involved in a pipe-bomb intimidation incident targeting Dublin drug dealer Charlie 'The Walrus' O'Neill, before the 53-year-old died of natural causes last August.
This criminal and another feared dissident Republicans were also the chief suspects for a savage torture attack in Co Limerick last November.
Investigations into the mob were stepped up after a viable bomb and a Glock pistol were seized and a Polish man was arrested after armed gardai pulled over and searched a vehicle near Mountrath, Co Laois, on February 25.
The seizure led to the closure of the M7 motorway for hours.