The man accused of murdering Gareth Hutch is in hospital after being stabbed in prison by a violent inmate.
Thomas Fox (29) was subjected to a vicious attack in Dublin's Mountjoy Prison at 11am yesterday. Dean Teeling (29) was being treated as the only suspect.
Fox, who has been charged with the feud-related murder of Hutch, was stabbed in the back of the head as he tried to intervene in an attack by Teeling on convicted murderer Michael Taylor.
Taylor (36), who was the main target of Teeling's attack, was stabbed in the stomach.
Teeling was placed in a special segregation unit at the prison after the incident.
The attack happened in the A Wing of the prison, which is the home of a number of criminals linked to the Kinahan cartel.
However, insiders said last night that the double stabbing was not being treated as feud-related and may be linked to a row that Taylor was involved in yesterday.
Taylor is serving a life sentence for the murder of Paul Kelly (26) at an apartment block in Clontarf, Dublin, in August 2007. His father, Michael Taylor Snr, was shot dead in 2011 in an unsolved murder linked to his son's crimes.
After Teeling attacked Taylor, Fox - a close associate and relative of Taylor - attempted to help his pal, but was stabbed before order was restored by prison officers. Fox has been charged with the feud-related murder of Hutch in the capital's north inner city last May.
Hutch (35), a nephew of Gerry 'The Monk' Hutch, was shot dead as he was getting into his car outside Avondale House flats on North Cumberland Street in Dublin on the morning of May 24 last year.
Fox is due to face trial in the Special Criminal Court.
While gardai and the Irish Prison Service have launched separate investigations into yesterday's stabbing, senior sources said the only suspect in the case was Teeling and no-one else was being sought.
Teeling will now face major disciplinary sanctions and possible criminal prosecution.
CCTV footage of the incident was being reviewed by prison officers and sources said that tensions remained high on the landing. Teeling is serving an eight-year sentence for several vicious blade attacks - including slashing a French tourist's face from his ear to his mouth.
His 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 sliced the Frenchman across the face with a razor.