Claims that the IRA has gone away are a "blatant lie", says the son of the only prison officer murdered in the Republic during the Troubles.
Austin Stack and his brother Oliver were driven to an undisclosed location in a blacked out van two years ago to get an IRA statement eventually admitting the organisation murdered their father Brian.
The meeting, organised by Sinn Fein leader Gerry Adams, proves the IRA still existed then, claims Mr Stack.
"The facts are that my brother and I actually met the IRA, so for Sinn Fein to now claim that they went away after the ceasefire is a blatant lie," he said.
The brothers held talks with Mr Adams and a former IRA commander for weeks in 2013 as part of a long campaign to secure a confession.
At the time, Mr Adams said he accompanied the two brothers to a meeting with an ex-Provo boss, who admitted the IRA shot their father in the back of the neck on March 25, 1983.
Brian Stack, a former Portlaoise chief prison officer, had been crossing a street after leaving a boxing contest at the National Stadium when he was gunned down. The IRA had always denied it was behind the killing.
"I met the IRA in August 2013, the IRA used its structures to get me information, Gerry Adams organised this meeting, are Adams and (Sinn Fein TD) Brian Stanley now claiming that this meeting never happened?" he said.
The Stacks were driven to a bungalow at an undisclosed location in a blacked out van where they were handed the IRA statement, printed up on a typewriter, and told to transcribe it.
The statement said their father's killing was "not authorised by the IRA leadership and for this reason the IRA denied any involvement".
It added that the Provo killers involved were acting under orders and that the IRA was responsible.