FOUR men and two women are being questioned by detectives investigating the murder of Eamon Kelly.
The 65-year-old convicted drug dealer was gunned down close to his home in north Dublin on Tuesday.
He was one of Ireland's most notorious criminals.
Last night a suspected dissident republican, Sean Connolly, 34, of Bernard Curtis House in Bluebell, south Dublin, was charged with his murder.
A Garda spokesman said six more people were arrested in Dublin this morning in connection with the investigation.
The four men and two woman, who are aged from their mid 20s to early 40s, and being questioned at Coolock, Ballymun and Raheny Garda Stations.
They can be detained for up to 72 hours under Section 30 Offences Against the State Act 1939.
Kelly, career criminal dubbed "the Godfather", was shot dead in broad daylight near his home in Furry Park Road in Killester, north Dublin.
Connolly, who was arrested close to the murder scene, was brought before a late night sitting of the three judge non-jury Special Criminal Court where he was charged with the killing.
He was also charged with possession of a Bloc semi-automatic pistol with intent to endanger life and membership of an illegal organisation styling itself as the IRA on Furry Park Road on December 4.
He will re-appear before the court via video-link on December 20, when his barrister is expected to make an application for legal aid.
Kelly was the 15th gun murder victim so far this year.
At least one other man is suspected of being involved with his killing.
He escaped a previous attempt on his life in 2010 when his attacker's gun jammed.
Kelly was jailed for 14 years in the 1990s for possession of 1kg (2.2lb) of cocaine and was sentenced for assaulting a Workers Party member in the late 1980s.
In recent years he has been portrayed as a close associate and confidant of ruthless gang leader and drugs boss Eamonn "The Don" Dunne, who was shot dead in a pub in Cabra, north Dublin, in 2010.
The probe into Kelly's murder focused on a bloody dispute between crime gangs and the Real IRA in north Dublin.
The leader of the terror faction, Alan Ryan, was murdered in September in a daylight gun attack.