Killeen has been a gangster since age of 16
NATHAN Killeen (24), is originally from O'Malley Park, Southill, Limerick.
He was integrated into the Dundon gang at an early age.
In 2006, following the murder of drug dealer 'Fat Frankie' Ryan in Moyross, Killeen - who was then aged just 16-years-old - was photographed with gang members behind a floral tribute from the Dundon brothers.
Despite his age, Killeen has already amassed 97 criminal convictions.
He is serving a five-year sentence for aggravated burglary after breaking into a house in Limerick to extort money.
Among his many convictions are 11 for drugs offences, 48 for road traffic incidents and 14 public order convictions.
Five years ago, Killeen infamously appeared on a YouTube video with John and Ger Dundon in which they openly threatened the life of convicted drug dealer Christy Keane.
His mother, Susan Killeen, took her own life while the trial was ongoing. Nathan's twin brother, Gavin, also died tragically.
His father, Gavin Devaney, from Sligo, is also dead after a suspected heroin overdose.
Two of Susan's brothers - uncles of Nathan - Eddie and Ray Casey, are well known to the guards and justice system.
At the Central Criminal Court in 2006, Edward Casey, was sentenced to 11 years in prison for the horrific aggravated sexual assault of a 23-year-old woman in Galway on September 30, 2004.
The young victim was walking through the Loch a' tSaile area of the city when Casey dragged her into a grassy bank and sexually assaulted her.
Ray Casey died in prison while serving a life sentence for the murder of a Limerick barman in 1997.
Noel Pyper, (48), the barman, was kicked to death in a Limerick laneway by Ray Casey and another man, Anthony Casey (no relation) on August 12, 1997.
The pair stalked their victim as he left a fast food outlet in the city centre on his journey home.
Ray Casey and his accomplice believed Mr Pyper was carrying the takings from the pub he had just finished work in. After pouncing on their lone target, they dragged Mr Pyper down a laneway. When they found he didn't have the money, they kicked him to death and left his body among refuse sacks.
The murder trial took nearly five years to come before a court because Ray Casey - who then had 53 previous convictions - changed his defence lawyers several times.
Casey died after collapsing in the exercise yard of Portlaoise prison.
A cousin of Nathan Killeen and son of Edward Casey, Stephen O'Sullivan, is serving a lengthy sentence for the gun killing of Mark Moloney in 2008.
A sister of Nathan Killeen, Ciara, is the partner of John Dundon who is serving a life sentence for the murder of Shane Geoghegan.