Gardaí investigating the murder of Vincent Ryan last month arrested a woman on Monday evening.
It is the fifth arrest in relation to the investigation into the shooting dead of the dissident republican in Finglas, Dublin.
Gardaí are continuing to question three men about the shooting. The men are being held in Garda stations across the city, with a fourth man detained last week having been released without charge.
The woman, in her early twenties, was arrested on Monday evening and she is currently detained at Finglas Garda Station under the provisions of Section 30 - Offences Against the State Act, 1939.
Some of those arrested are linked to senior gangland figures in west Dublin suspected of a string of armed robberies, including on cash in transit vans, that netted millions of euro.
Ryan is believed to have been shot dead at the behest of another drug dealer and armed robber who lives in north Dublin.
That gang leader, like other underworld figures, was targeted by the Real IRA in Dublin when it was led by Alan Ryan, a brother of Vincent Ryan.
Alan Ryan (32) was shot dead in north Dublin in September 2012 by gang leaders because of the threat he posed to them. The same men are suspected of Vincent Ryan’s murder last month.
The latest suspect to be arrested in connection with Vincent Ryan’s killing was detained in west Dublin on Saturday and taken to Blanchardstown Garda station.
The man, who is in his 30s, was being questioned under section 50 of the Offences Against the State Act and can be held for up to seven days without charge.
The two other men being held last night were detained late last week and were being questioned at Blanchardstown Garda station and Finglas Garda station, where the murder inquiry is based.
One of the men, aged 43, was detained last Thursday; the other, in his 30s, was arrested, along with the man since released, during searches in north and west Dublin last Tuesday.
Vincent Ryan (25), a father of one, was shot dead in a gangland-style attack as he sat in a car outside his partner’s family home on McKee Road, Finglas, on February 29th.
At his funeral in Dublin earlier this month, teams of uniformed gardaí, armed detectives, members of Regional Support Unit and the Emergency Response Unit were present.
Personnel from the Garda’s Public Order Unit were on standby near the church in case of any public-order issues or efforts to form a paramilitary colour guard.
In 2012 when Ryan’s brother, Real IRA leader Alan Ryan, was shot dead, shots were fired over his coffin before his funeral Mass. Gardaí claimed they had been assured by his family there would be no such display. The scenes were not repeated at Vincent Ryan’s funeral.