Twelve days ago Northern Editor Suzanne Breen interviewed the daughter of a former IRA commander who has made very serious allegations of physical and sexual abuse against a serving Sinn Féin elected representative. The woman, who approached the Sunday Tribune, outlined how she suffered unspeakable abuse, including being made to drink her own urine as a 10-year-old in 1980, beatings and being locked in a dog kennel.

Sinn Féin leader Gerry Adams and others in SF were informed of the terrible details of the allegations against this person. At one stage Gerry Adams promised to have this alleged abuser expelled from the party.

On interview this woman gave the Sunday Tribune documentary evidence from her school and social workers of her situation as a child. She was subsequently taken out of this individual's care.

She posed for photographs in Belfast and after being read the contents of the story by Breen, agreed completely with it and with its publication. Forty-eight hours ago this woman was happy to be identified and to put her case about Sinn Féin cover-ups. However, under intense pressure yesterday she withdrew her consent at the eleventh hour and sought, through the Belfast solicitors' firm Madden and Finucane, to have no details published whatsoever.

Today we honour her request for anonymity, but we publish the horrifying details of what she says happened to her as a child and how she alleges Sinn Féin and Gerry Adams failed to act. She is one of two very young, very defenceless and very vulnerable young women, both members of families who are the equivalent of republican royalty – the daughter of a legendary IRA leader and the grand-niece of none other than the founder of the IRA and its chief-of-staff – that Gerry Adams and Sinn Féin were informed had been sexually abused.

Joe Cahill's grand-niece tells a story similar to that of Aine Tyrell, Liam Adams' daughter. Like Aine Tyrell, she was forced to confront her abuser by an unsympathetic Seamie Finucane, brother of murdered solicitor Pat Finucane, who repeatedly asked her to withdraw her allegations. It was only when other teenage girls claimed they were sexually assaulted by the same man that the republican movement re-opened its investigation into the sex abuser, but even then, the man responsible was allowed to cross the border to escape justice. "Sometimes these things happen," Gerry Adams told her.

When told by the mother of two other children this man attacked sexually that this serial abuser had been spotted drinking in a bar in Letterkenny, Adams asked her: "What do you want me to do, bar him from every bar in Ireland?"

The handling by Gerry Adams of allegations of child sex abuse by his brother Liam of his daughter has been met with a strange mixture of silence and disquiet.

Sinn Féin's defensive reaction has been incomprehensible. Its reaction is even more disturbing given that it wants to be accepted as a democratic party that, at this very moment, is negotiating devolution of policing and justice powers which will inevitably involve investigation of rape and child abuse.

It would surely, right-thinking people could be forgiven for thinking, be in the interests of the party North and South to admit that it and its leader have made grave mistakes. Then it could begin the major task of convincing the electorate that enough procedural changes have been made within the party and its structure to ensure this sort of unacceptable reaction is never repeated.

But, as our stories today reveal, that cannot happen. It cannot happen because the extent of the cover-up of child abusers within the republican movement by its most senior leaders stretches far beyond Gerry Adams and his desire to protect his brother. Similar allegations against other very senior republican figures have been suppressed as, in the words of one of the abused women, "a few powerful individuals put the preservation of the movement and their own position above the safety of children".

Adams admits himself that he could have handled the allegations made by his niece better. It has also been suggested that his own family history of abuse of his siblings by his violent father may have had an impact on his judgement.

That emotional admission of personal experience of abuse – volunteered by Adams himself – has become a distraction to the central criticism of the SF leader, which these new cases reinforce. Adams has put the welfare of not just his brother, but also other senior republicans, and the image of the movement, before that of children.

He has still not satisfactorily answered the many questions raised by this newspaper, which are entirely relevant to how a senior political figure, a party leader, a policy maker, should act when confronted with allegations of serious crime against children.

Sinn Féin chairperson Declan Kearney claims "political opponents have chosen to cynically exploit this tragic situation for wholly political ends. This is disgraceful."

One wonders where the cynicism really lies.

If Sinn Féin wants to be taken seriously as a political force with authority to speak on issues of such sensitivity as paedophilia, rape and child abuse, then it must clean itself up fast.

Its members and officials who have evidence of abuse must do what every teacher, lecturer, childcare worker, priest, swim coach or scout leader is obliged to do by law: report it to the police.