GANGSTER Ger Dundon was beaten to a pulp in prison.
The notorious thug was left "battered" by Ian Horgan, who raped and killed a young woman.
They became involved in a punch-up after Dundon threatened a female associate of Horgan.
"There was blood everywhere. Dundon was beaten to a pulp," said a source.
Dundon – a senior figure in the McCarthy/Dundon gang – required extensive hospital treatment after the incident in Wheatfield Prison.
Horgan (29) is serving sentences totalling 16 years for manslaughter, rape and robbery, while Dundon (26) is serving five years for violent disorder and threats to kill.
A jail insider revealed: "Horgan is a complete headcase and Ger got more than he bargained for when he started making threats about Horgan's pal.
"Horgan gave Dundon a fair old beating. He had injuries to his lips, forehead and nose.
"Prison staff finally got Horgan away from him. Ger was then rushed to St James's Hospital for emergency treatment for facial injuries."
Horgan, who is originally from Ballincollig, Co Cork, has now been transferred out of Wheatfield Prison as a disciplinary measure. Sources say that "this is the best thing for him" because Dundon and some of his Traveller associates in the jail were plotting a revenge attack.
The source added: "This simply would not have happened to Ger Dundon or any Dundon in prison even three years ago, so it shows how far down the pecking order his gang has gone.
"The Dundons used to rule the prisons they were in with an iron fist.
"Everyone was terrified of them, but not any more." Horgan was convicted over the death of beautician Rachel Kiely in 2000.
Rachel was found strangled in the Regional Park in Ballincollig, Co Cork, in October 2000.
Horgan was aged just 16 and was a neighbour of the devout Jehovah's Witness, who was out walking her dog when she was raped and killed.
In 2006, he pleaded guilty to Rachel's manslaughter and was also found guilty of her rape.