Sinn Féin president Gerry Adams has said he believes claims made by a man that he was raped by a senior IRA member.
Paudie McGahon was 17 when the alleged assault took place in County Louth.
However, Mr Adams did not clarify whether he believed Mr McGahon's claims that he was subjected to an IRA "kangaroo court".
Mr McGahon said he wants the republican movement to acknowledge the truth of his story.
Mr McGahon told the BBC's Spotlight programme that an IRA man, from a well-known republican family in Belfast, abused him and then threatened him to remain silent.
He said he was later subjected to an IRA "kangaroo court" after a Sinn Féin representative was told of the allegations.
Speaking on RTÉ radio, Mr Adams said he only found out about the incident in 2009 when he was told by Sinn Féin Louth TD Arthur Morgan.
He said Mr McGahon's alleged perpetrator should come forward.
When asked on Wednesday by Irish broadcaster RTÉ about Mr McGahon's claims that he was subjected to internal IRA inquiries, Mr Adams said: "I don't know - the fact is there is a garda investigation under way."
In the BBC programme, Mr McGahon said the IRA offered to kill the alleged rapist but instead expelled him to England.
Mr Adams, when asked on Wednesday if the man had been exiled in 2002, said: "He may well have been and that's wrong. I don't have anything to contradict what he has said."
"The fact is that the IRA should not have been near any of these cases whatsoever - that was inappropriate," he told RTÉ.
"The only people to deal with these matters are policing agencies, PSNI and (the Republic of Ireland's police service) An Garda Siochana."
Recalling his experiences, Mr McGahon told the BBC that when he tried to escape from his alleged rapist, he was told if he ever opened his mouth about it anybody he would be found on the border roads.
He said he felt he could not report the matter to Irish police because of the threats he had received.
Mr McGahon said that for years, he told no-one about what had happened.
But in 2002, he said he broke his silence on the alleged abuse, and a local Sinn Féin representative was informed.
Mr Adams said on Wednesday that he first heard about the allegations in 2009 "when the young man went and met with the then local TD, Arthur Morgan, and he had been previously been dealing intermittently with (Sinn Féin councillor) Pearse McGeough".
The Sinn Féin president said Mr Morgan had written to Mr McGahon to advise him to make a formal complaint to police.
"Sometime around that time I was simply briefed, not in the detail, but that there was a sex abuse allegation and that Arthur had dealt with it in that way," he told RTÉ.
Asked why he did not know about it before 2009, he said: "You have to bear in mind that Sinn Féin have councillors the length and breadth of this island, these matters are matters of confidentiality between them and the people they are dealing with."
Mr McGahon's claims follow similar allegations made to the programme by Belfast woman Maíria Cahill last year.
It is five months since Ms Cahill waived her right to anonymity as an alleged victim of sexual abuse to tell her story of how Sinn Féin and the IRA dealt with her claims that she had been raped by an alleged IRA man when she was 16.
Since then republicans have repeatedly questioned her version of events.
In the BBC's Spotlight programme, Mr McGahon claimed senior republican Padraic Wilson, 55, was involved in the kangaroo court meetings he said he was subjected to.
In a statement issued through his solicitor on Tuesday, Mr Wilson said he does not know nor has he ever met Mr McGahon.
Mr Wilson said he refuted the allegations made by Mr McGahon.
Mr Wilson said he he had previously offered to assist the garda investigation in an effort to "clear up this matter".
Meanwhile, Sinn Féin MP Francie Molloy has apologised for writing on Twitter: "Another load of rubbish on Spotlight tonight."
"I apologise for any offence my post caused to Paudie McGahon or any victim of abuse," he said on Wednesday.
He added: "These matters are best dealt with in the justice system rather than trial by television and it is my hope that justice will be done."