Sinn Fein leader Gerry Adams has repeatedly denied any knowledge about a string of murders believed to have been committed by the Provisional IRA.
It came as Mr Adams attempted to clarify an apology that he made in the Dail in January this year to the families of victims of republican violence.
At the time he apologised to the families of Garda Jerry McCabe, Garda Ben O'Sullivan and the families of other members of state forces killed in the conflict.
“I'm very sorry for the pain and loss inflicted upon those families,” he said.
However, when asked to clarify the apology in an interview with Miriam O'Callaghan on RTE's Prime Time on Monday, Mr Adams issued a string of denials.
He denied being the final “court of appeal” in the suspected IRA murder of innocent farmer Tom Oliver in 1991. “Of course I deny it,” he said.
Ms O'Callaghan put it to the Sinn Fein leader that it was widely believed that this was the case. Mr Adams then demanded to know the journalist's sources. He admitted that the killing was not justified.
Asked about the murder of the chief prison officer in Portlaoise, Brian Stack in 1983, Mr Adams said: “I don't know who killed him”.
Asked about the murder of Garda Samuel Donegan, who died in a bomb blast after straying just over the border in 1972, he said: “I don't know who killed Garda Donegan”.
He also accused those who said that he had ordered the killing of innocent Jean McConville in 1972 of “telling lies” and wanting him dead. “They thought I'd sold out,” he said.
Mr Adams said he believed that any killing of a human by another human was “murder” and that the killing of agents of the state was wrong.
But he said that violence and killing was part of war. “I don't distance myself from the IRA. Until the day I die I will never distance myself from the IRA,” he said.
Despite obvious tensions on camera, Ms O'Callaghan said the atmosphere thawed as soon as the programme was off-air.
She said the mood was nothing like in 2011, when Martin McGuinness went to her dressing room following the presidential election debate.
“I'm always very polite and friendly before and afterwards. I just said to Gerry: 'Thank you for coming in, I appreciate it'.
“It was actually fine. Those interviews are always very stressful, mainly for the interviewee, but also for the interviewer. I put a lot of work and preparation into it and I think he had too. It did get very robust. I was just holding my ground.”
When asked if she considered Adams evasive, the mother-of-eight said: “I've interviewed Gerry for 23 years, since 1990. I respect him greatly and respect his role in the peace process greatly, but I think it's my job, when you see families who are still very affected by the Troubles, to ask tough questions.”