Paudie McGahon has accused Sinn Féin representatives of "continuing to lie and blur the truth" in a bid to cover up the party's failings.
The abuse victim revealed that the party was "fully aware" in 2002 that his attacker had also sexually assaulted a much younger boy and posed a threat to children living in County Louth.
Deputy leader Mary Lou McDonald and other party representatives yesterday claimed that Sinn Féin's reporting guidelines for sexual abuse in 2009 only pertained to party members.
However, last night Mr McGahon said that the IRA member who raped him at the age of 17 and also sexually abused another much younger boy, was in fact a member of Sinn Féin.
"I grew up in Sinn Féin and I know that every IRA volunteer must be a member of the party so this is just another example of them continuing to lie and blur the truth to get themselves out of this," he told the Irish Independent.
The controversy over allegations that Sinn Féin members organised an IRA kangaroo court to interrogate Mr McGahon and a second man in 2002 deepened yesterday.
He described "a cynical ploy" which was used to prevent him from going to the gardaí when a Sinn Féin member told him that reporting the paedophile would set back the recovery of the other victim, who was suffering from alcoholism.
He had also been warned by his attacker and another IRA member that he would be killed if he ever went to the media or the gardaí.
"Sinn Féin and Adams and McDonald are digging bigger holes for themselves as they continue to try and undermine what I have said," he said.