A murder suspect suffered serious injuries when he was stabbed in the head at Mountjoy Prison.
Thomas Fox (29), who has been charged with the murder of Gareth Hutch, was knifed after a row broke out in the jail yesterday morning.
The incident began when convicted killer Michael Taylor (36) was stabbed in the torso by another inmate. Mr Fox was stabbed by the same attacker when he attempted to intervene in the violent clash.
The Irish Independent can reveal that Dean Teeling (29) is the only suspect for the shocking incident, which happened at around 11am in the A wing of the prison.
This area of the prison is home to a number of criminals linked to the Kinahan cartel, who are involved in a feud with the Hutch gang.
However, jail insiders said last night that the double stabbing is not being treated as feud-related and may be linked to a row that Taylor was involved in on Monday.
Taylor is serving a life sentence for the murder of Paul Kelly (26) at an apartment block in Clontarf, Dublin, in August 2007.
Gardaí and the Irish Prison Service have launched separate investigations into the Mountjoy incident.
Senior sources said the only suspect in the case was Teeling. He will now face major disciplinary sanctions and possible criminal prosecution.
Teeling is serving an eight-year sentence for several knife attacks, including slashing a French tourist's face from his ear to his mouth.
The criminal's 81 previous convictions include thefts, robberies, criminal damage and firearms and drugs offences, and he has been involved in a number of feuds.
Dublin Circuit Court heard in November 2015 that Teeling repeatedly stabbed a man, before slashing the tourist and another stranger across the face with a razor blade in unprovoked incidents a year later.
Teeling, of Cappagh Avenue, Finglas, Dublin, pleaded guilty to violent disorder and assaulting Ian McKenna, causing him harm, at Central Bank Plaza, College Green, on September 9, 2013.
He also pleaded guilty to assaulting Gerard McKeever at McDonald's, Lower O'Connell Street, on April 24, 2014, and assaulting French tourist Loic Marie-Magdaleine on Fleet Street, Temple Bar, later on the same date.
Teeling stabbed the then 28-year-old Mr McKenna eight times as he lay on the ground after being punched and kicked by three others.
Mr Marie-Magdaleine was walking home with friends when his brother, Lionel, bumped into a drunk woman on Fleet Street a short time after the McDonald's attack.
This woman "told the brother where to go" when he asked if she was alright and walked into a nearby pub. Teeling then came out of the same pub and stabbed the Frenchman across the face with a razor.