Gerry Adams has aligned his party with the campaign to bring the killers of Belfast man Robert McCartney to justice, and accused opponents of exploiting the McCartney killing and the Northern Bank robbery for political gain.
The Sinn Féin leader last night warned an expulsion process would begin against suspended party members unless they made "full and truthful" statements on the murder. While acknowledging there was unease in the party about the issue, he told RTÉ's The Week in Politics he was "duty bound" to suspend without prejudice members who had been named by the McCartney family.
Meanwhile, former taoiseach and now EU representative in Washington John Bruton told a US audience that Mr Adams was a leader of the IRA, and warned that it would be "very, very dangerous" for the Republic if Sinn Féin was to hold the balance of power in the Dáil while tied to a secret army.
In a television interview on NBC and PBS, Mr Bruton replied "yes" when asked if he believed Mr Adams was in the top leadership of the IRA.
In a move designed to begin repairing the damage done by the McCartney killing, the Sinn Féin leader invited his five sisters to sit in the front row of the party's weekend ardfheis to hear his demand that those responsible admit their guilt in a court of law.
And although the sisters later expressed their appreciation for the invitation, they told reporters they would judge Sinn Féin's response not on Mr Adams's words but on whether those who killed their brother ended up being convicted.
"The bottom line is that, until those who committed Robert's murder and their accomplices are brought to justice and appear in court, we will not accept that everything that can be done has been done," said Catherine McCartney.
Sinn Féin is expected to continue in the coming days to put pressure on those who carried out and witnessed the killing to make statements in the hope that the stream of damaging publicity can be brought to an end.
The McCartney sisters sat without applauding in the front row of the hall as Mr Adams said the family's demand for justice and truth was "a just demand", and he pledged his and Sinn Féin's support.
"Those responsible for the brutal killing of Robert McCartney should admit to what they did in a court of law . . . Others with any information should come forward.
"I am not letting this issue go until those who have sullied the republican cause are made to account for their actions."
He also made a strong denunciation of so-called "punishment attacks", saying: "Our party has a lengthy opposition to these. They are counterproductive. They should stop."
He said later, however, that opponents of Sinn Féin "are exploiting both the tragic death of Robert McCartney and accusations round bank heists. Sinn Féin wasn't involved in the bank heist. Sinn Féin is not involved in criminality."
Both Mr Adams and the party's policing spokesman, Gerry Kelly, told delegates that the party was committed to changing its policy and possibly accepting the policing structures in Northern Ireland.
Mr Kelly said significant progress had been made on this issue in talks, and it was possible that all outstanding difficulties could be resolved at some point.
Mr Adams reminded delegates that he had agreed to ask the party's ardchomhairle to call a special ardfheis to reconsider their attitude to the PSNI in the event of the party achieving its objectives in the area of police reform.