A GARDA killer who walked out of a low security jail had escaped from the same prison before.
It has emerged that Martin McDermott had beaten the system at Loughan House four years ago.
An investigation also found that while officers noticed he was missing they were distracted for a time by another prisoner who tried to hang himself with a pillow case.
Justice Minister Alan Shatter has now admitted that it was wrong to transfer the 26-year-old to the jail.
McDermott was found guilty in 2009 of the manslaughter of Garda Gary McLoughlin and sent to Portlaoise Prison. He was jailed for eight years with the last year suspended and disqualified from driving for 20 years.
He was transferred to Loughan House open prison in Cavan earlier this month but walked out 12 days later and absconded to Derry where he was later arrested.
The Prison Service last night blamed an unnamed prison official for transferring the criminal, who has 91 convictions. Service director general Michael Donnellan said: "The decision maker did not attach sufficient weight to the gravity of the offence for which the offender had been sentenced when making this decision."
Commenting on the gaffe, Mr Shatter said "it is impossible to avoid the conclusion that this decision was wrong. First and foremost in making the decision, sufficient consideration was not given to the gravity of the heinous offences which had been committed. Neither was adequate consideration given to other criteria that should have been taken into account".
The internal report into the escape showed McDermott was missed during lunch time and a search of the grounds was ordered.
McDermott previously escaped from Loughan House while serving a three month sentence in November 2007. He was apprehended five days later.