Detectives investigating the murder of Real IRA terror chief Alan Ryan have arrested a woman as part of their major investigation into the 2012 gun killing, the Herald can reveal.
The woman, who is aged in her early 30s and from the Kilbarrack area of north Dublin, was questioned at Coolock Garda Station and was detained last night.
It is understood that she is the first female to be arrested in relation to the murder and she is being held on suspicion of withholding information.
Sources said that since Ryan's murder, she has mostly been based in Northern Ireland but has made sporadic journeys to Dublin. She was arrested in the capital yesterday on suspicion of shoplifting at a store on the northside.
After her arrest for this offence, detectives then re-arrested her in relation to Ryan's murder.
The woman is not suspected of having any active role in the murder, but is believed to have key information about the activities of the 'Mr Big' drugs gang that carried it out.
The Herald has learnt that the woman is the girlfriend of a major figure in the gang.
This 31-year-old north-Dublin man is known as one of the best getaway drivers in the capital's criminal underworld and is suspected of acting as a driver in a number of other serious gangland crimes.
The most notorious of these crimes is the double murder of cousins Glen Murphy (19) and Mark Noonan (23), who were gunned down on the forecourt of the Tesco Clearwater filling station on November 23, 2010, in a sickening case of mistaken identity.
It is not known if the 31-year-old had any involvement in Alan Ryan's murder, or what his arrested girlfriend actually knows.
Alan Ryan was shot dead by the drugs gang led by so-called 'Mr Big' in September 2012 after a massive cash row between the two mobs.
There have been a number of other arrests including low-level gangster Paul 'Ralph' Gallagher, who was shot dead in a Co Meath field last month as part of an unrelated dispute.
Two men who have been arrested in relation to it have been charged with withholding information about it.
One of these men, Robert Carroll (28), whose last known address was Ard Cluain, Clonee, Co Meath, has since fled to England where a court ruled that he could not be extradited.
A number of other men have been arrested about the Ryan murder and have been charged with separate serious offences.
Ryan (32) was shot dead as he walked with friends at Grange Lodge Avenue in Clongriffin, north Dublin, on the afternoon of September 3, 2012.
Sources said that detectives have not yet "definitely identified" the tall hitman who killed him in a shooting that was captured on CCTV.
However, senior sources are satisfied that the gang who murdered Ryan had been at war with him for over a year before they murdered him.
Tensions are expected to increase in north Dublin in the coming days ahead of the second anniversary of the murder.
It is expected that plain-clothes gardai will be patrolling and monitoring areas around north Dublin and there will be a more visible garda presence in Donaghmede and Clongriffin over the coming fortnight.