Admission that IRA killed prison officer Brian Stack
The IRA has admitted killing the only prison officer murdered in the Republic of Ireland during the Troubles.
Thirty years after the attack on Brian Stack, Sinn Féin leader Gerry Adams has expressed his "regret" to the Stack family over the killing.
The family of the former Portlaoise chief prison officer had mounted a long campaign to secure the admission.
It came after Mr Stack's sons Austin and Oliver held talks with Mr Adams and a former IRA commander.
Austin Stack told the BBC: "The IRA initially denied the murder of my father - right up until the end of March senior Sinn Fein politicians were denying the murder.
"The most important thing we got was that the IRA have now admitted responsibility for the murder of my father, they have admitted that IRA members acting under instructions carried out the shooting of my father.
"They told us they had disciplined the IRA member who had issued the instruction. He (the IRA commander) expressed regret and he expressed a lot of sorrow for the hurt and pain - he did that several times and he did appear quite remorseful."
Mr Stack had accepted that even if someone was brought to justice for the killing they would spend very little time in prison due to the terms of the Good Friday Agreement.
"The meeting meant an awful lot to myself and to my family because we now have an element of closure. It doesn't bring us whole closure, but it does bring us about 90% of the closure we're looking for.
"It was really significant for us to actually get the IRA to admit responsibility for this, because my father's good name has been kind of hanging there for the last 30 years and today we can actually say to the public and to the world the IRA have now admitted they killed my father.
"My father is looking down on us today and I'm sure he's a happy man, because we got the answers that we were looking for."
Mr Stack had been crossing a busy Dublin street after leaving a boxing contest at the National Stadium when he was attacked.
There have been three separate police investigations, and so far no individual or organisation has been found responsible for the prison officer's murder.
Mr Adams said he accompanied the two brothers to a meeting with a former IRA commander, who admitted the IRA shot their father in the back of the neck on 25 March, 1983.
In a statement, the commander said Mr Stack was murdered as a reaction to the "brutal" prison regime in Portlaoise.
He said the killing had not been authorised by the IRA leadership and this was why the IRA denied any involvement.
The statement continued: "Some years later, when the army council discovered that its volunteers had shot prison officer Brian Stack, the volunteer responsible for the instruction was disciplined".
On Friday, Mr Adams said: "I want to pay tribute to the Stack family, to Sheila Stack and her sons, Austin, Kieran and Oliver.
"On behalf of Sinn Féin I extend my regret at the killing of Brian.
"I hope that these recent developments will help them achieve the closure they have sought for 30 years."
Brian Stack was left paralysed and brain-damaged from the shooting and suffered for a further 18 months before dying from his injuries at the age of 47.