Published Tuesday, 26 June 2012
The prisoner was found dead on Monday. (© UTV)
Christopher Stokes, aged 37, was found in a collapsed state in his cell on Monday night.
Staff tried to revive him but he was pronounced dead just before midnight.
Mr Stokes, who was originally from Derry, was given a minimum 20 year tariff last year for his part in the murder of John Mongan in west Belfast.
A father-of-three, Mr Mongan was killed in front of his heavily pregnant wife Julia in 2008. He suffered up to 50 wounds - some of those were possibly inflicted by a sword or machete.
The PSNI, Coroner and Prisoner Ombudsman have been notified and investigations are ongoing.
His family have also been informed.
Prison Service Acting Director General Max Murray said: "On behalf of the Northern Ireland Prison Service, I would like to extend my sympathy to the family. This is a tragedy and my thoughts are with them at this difficult time."
Stormont justice spokesmen Alban Maginness, SDLP and Raymond McCartney, Sinn Féin, also extended their sympathies.
"The Prison Administration needs to address all the flaws in the system which can result in this type of tragedy immediately," Mr McCartney said.
© UTV News