Dumbrell attacked ex-officer in jail cell
Notorious killer Warren Dumbrell faces disciplinary action after a prison attack on a jailed former prison officer.
Dumbrell (below) picked the wrong target in the Midlands prison when he lashed out at fitness fanatic Dillon O'Brien.
The former prison officer who is serving four years for trafficking drugs and phones into Mountjoy.
Despite a cocaine addiction, O'Brien has always maintained a strict fitness regime while behind bars.
He got involved with serious crime figures and trafficking when he was pumping iron at a Blanchardstown gym.
Dumbrell attacked him in Portlaoise Prison as he was mopping a floor. It's understood Dumbrell was coming back from the gym when he seized the opportunity and attacked O'Brien.
The specially built segregation unit at the jail houses prisoners who have to be isolated for their own safety or the safety of others.
The logistical nightmare of catering for jailed gardai, prison officers and murderers is resolved by organising separate recreation periods and practically zero contact.
"The two came into contact briefly and there was a bust- up," said a prison officer.
Dumbrell, from Inchicore, is serving life for stabbing Christy Cawley to death in front of his wife and children in a flats complex in Dublin.