Peter Murray (35) – who has been in custody since beating and stabbing a man to death in 2002 – did not return to the detention facility on Sunday evening after being allowed out on temporary release.
Sources say authorities in Shelton Abbey – a low security Irish Prison Service facility in Wicklow – notified gardaí on Sunday evening.
It’s believed Murray may now be lying low in Dublin.
Sources say Murray, who has spent the last 20 years in custody, was nearing the end of his sentence and had been sent to Shelton Abbey as a means of helping him reintegrate into society ahead of a release on licence.
He was considered to be at ‘very low risk’ of absconding.
The killer, with a former address at Donomore Crescent, Killinarden, Tallaght, was sentenced to life in prison in 2005 for the murder of the father of his girlfriend's child.
He had pleaded not guilty to the murder on April 12, 2002, of Peter Bisset (23), Cushlawn Park, Tallaght.
Mr Bisset died early that morning shortly after being beaten and stabbed outside his ex-girlfriend's home on Donomore Crescent.
Murray’s girlfriend, Catherine Hoare, testified that Mr. Bisset had tried to defend himself from the attack, while curled up on the ground.
During the trial, the court heard that, when first approached by gardai, Murray denied knowledge of the incident.
The jury saw forensic evidence showing Mr Bisset's blood on the accused's clothing.
When he finally admitted to killing Mr Bisset with part of the deceased's child's cot and a kitchen knife, Murray said he did not care for how long he would be locked up because the victim deserved to die.
Retired State Pathologist Professor John Harbison said his post mortem showed the victim bled to death due to a stab wound.
After the verdict was read out, the deceased's mother, Mary Bisset, told the court her son's death had devastated her family.
Det Sergeant Robert Barber told the 2005 sentencing hearing of Murray's troubled life and convictions.
Murray had moved from foster home to hostel throughout his teens, having lost the support of his parents by age 10.
Det Barber agreed Murray had raised himself on the streets and had become a heroin addict.
Murray had been in custody since being arrested on the day of Mr Bisset's death.
Det Barber confirmed the convict had been rehabilitated since his incarceration in Wheatfield Prison.
He was now a different man, the court heard.
In a statement, the Irish Prison Service confirmed: “The Irish Prison Service can confirm a prisoner absconded from Shelton Abbey on the 12th June 2022.
“An Garda Siochana have been notified.
“When a prisoner absconds An Garda Síochána are informed and they have the power to detain, arrest, and return such persons to prison.