A feared Ballymun gangster suspected of being one of the shooters who murdered Gareth Hutch is being questioned by gardai.
The thug, aged in his 30s, was arrested at the weekend under section 50 of the Criminal Justice Act in relation to the murder.
Dad-of-one Gareth Hutch was gunned down near his home at Avondale House in Dublin's north inner city on May 23 in the latest murder in the deadly Kinahan-Hutch feud which has claimed seven lives.
The career criminal, who is now in custody, has some 80 previous convictions for offences including threatening to kill a woman, drug dealing, criminal damage, road traffic and possession of firearms.
He was released from prison last year.
On top of his organised crime connections, the north Dublin man also has connections with a well-known Dublin businessman, who has been the subject of garda raids in the past but has denied any involvement in crime.
The arrested criminal was previously involved in another feud that gripped Ballymun after a man was shot in the back of the head more than a decade ago.
Shocking CCTV showed the moment Gareth Hutch was set on from behind by two men as he was about to get into his car. He was shot several times and the two men escaped on foot.
It came just 24 hours after Mr Hutch had confided in a local councillor that he feared he would be shot in front of his young son and was requesting a move to a different apartment which would be safer.
The latest arrest came after two people were charged in connection with the killing of Gareth Hutch.
Thomas Fox has been charged with the unlawful possession of a handgun - a Markarov 9mm - in connection with the murder.
Fox, of Rutland Court, Dublin 1, has been further remanded in custody and will appear in court again on June 22.
He faces up to 14 years in prison if found guilty.
Mary McDonnell (43), with an address at Avondale House, has also been charged and is accused of withholding information from investigating officers. She is due in court again next week.