The family of Frank Hegarty, executed by the IRA as an informer, have said it's "complete nonsense" for Martin McGuinness to claim his only reason for refusing to clarify his role in events is to protect them from further pain.
Presidential candidate Mr McGuinness has denied that he told the family it would be safe for their brother to return home and that the IRA wouldn't harm him.
The Sinn Féin politician said it would be "very hurtful and very damaging to the family" if he gave a full account of events of how Hegarty was persuaded it was safe for him to escape his British intelligence minders in England and return home to Derry.
Mr McGuinness alleged that one member of the family really knew what had happened but added: "I am not going to put that person in a predicament".
However, the sisters of Frank Hegarty, whose body was dumped on a lonely border road in May 1986, last night accused Mr McGuinness of talking "total rubbish".
They told the MoS: "We don't know what Martin McGuinness is talking about. How on earth could he possibly hurt us any more than he has already done?
"Martin McGuinness inflicted tremendous hurt on us when he falsely assured us it would be totally safe for our brother to meet the IRA, only for Frank then to be killed. The ultimate hurt was inflicted on us when Frank was murdered. We have been living with that hurt for 25 years."
Speaking from their Derry home, the three sisters said Mr McGuinness was erecting a smokescreen to hide his role in events leading up to their brother's murder.
"By claiming he cant give a comprehensive account of what happened because it would hurt us, Martin McGuinness is doing what Sinn Féin always does in difficult situations – using an excuse to avoid telling the truth."
Responding to media questioning this week, Mr McGuinness denied telling the family that it would be safe for Frank Hegarty to meet the IRA in Co Donegal in May 1986. It was the last time Hegarty was seen alive. When his body was found on a Co Tyrone road, his hands were tied behind his back and his eyes were taped. He had been shot in the back of the head.
The Hegarty sisters said: "We drove Frank to meet the IRA in a hotel car park in Buncrana as had been arranged. Why would we take Frank to meet the IRA if Martin McGuinness had advised us not to or if we thought Frank was to be murdered?
"It would be completely illogical that we would knowingly drive our brother to his death." The Hegarty sisters said they categorically stood over both their own account to the MoS last week, and their mother's account to ITV's The Cook Report in 1993, of Mr McGuinness's role.
"Martin McGuinness got down on bended knee and held our mother's hand when she was crying and promised that no harm would come to Frank when he met the IRA," the sisters said.
"Our mother told the truth to the Cook Report 18 years ago and we are telling the truth now. We stand by everything we have said. We have nothing else to add."
In relation to Frank Hegarty's murder and his own paramilitary activity, Mr McGuinness said that people in Northern Ireland weren't "obsessed by any of this". He added: "The reality is that the past is a very, very dark place for everybody."
The Hegarty sisters said: "For those of us who have lost loved ones, the past is not something that can be easily dismissed – it is with us every day."
Sinn Féin failed to return calls yesterday on any issues relating to Mr McGuinness.
