Dundon was back in A5 unit of Portlaoise Prison yesterday after both he and Killeen were handed down life sentences for the cold-blooded killing of businessman Roy Collins.
The 35-year-old father-of-two was shot dead as he worked in the family business in Limerick on April 9, 2009.
The intended target was his father, Steve Collins, who had assisted gardaí in a previous probe against the Dundons.
The Special Criminal Court found Wayne Dundon, 36, guilty of ordering the hit by mobile phone from his cell in Wheatfield Prison. Killeen, 24, was the getaway driver for the gunman, James Dillon, who has already been convicted.
Wayne, joins his brothers, John and Dessie, who are both serving life sentences for separate murders. Killeen is the brother of Ciara Killeen, the partner of John Dundon.
The four of them are kept separate from other gangland criminals and subversives, who are housed in Block C and Block E respectively.
The criminals include rival Collopy gang members, including Kenneth and Brian Collopy and their cousin Shane Mason.
A fifth man is also housed with the Dundons on A5, but he is not linked to them.
“Effectively, to all intents and purposes, the Dundons are completely separate from the rest of the prison population,” said one jail source.
He said that while there are other inmates in the A Block, they are housed on separate landings, with no interaction with the Dundons. The other prisoners in the A Block are there for punishment and are often on 23-hour lock-up.
A Block has its own gym and yard and any education or classes are brought to the Dundons, preventing interaction with other inmates.
“They are kept separate in a secure area,” said the source. “That prevents them threatening other prisoners or exerting undue influence on them.”
Wayne Dundon has 28 P19s, or prison disciplinary sanctions, since 2001 (five since 2011) for assaults, possessing contraband and disobeying orders.
John Dundon, 31, is serving life for the murder of Shane Geoghegan, shot dead in a case of mistaken identity in November 2008. Dessie Dundon, 30, is serving life for the murder of rival crime boss Kieran Keane in January 2002.