The co-author of a biography of Martin McGuinness said yesterday she would not reveal the names of former IRA men who have made controversial allegations against the Sinn Féin MP.
Ms Kathryn Johnston, who co-wrote the book Martin McGuinness: From Guns To Government with her husband, Sunday Times journalist Liam Clarke, said many of the sources for the book "are afraid for their personal safety if their identities became known".
Ms Johnston also told the Bloody Sunday Inquiry yesterday that her sources had told her that Mr McGuinness's brother Willie, nicknamed "The Grim Reaper", and the former leader of the Provisional IRA in the Maze Prison, Raymond McCartney, had visited people "in an attempt to prevent them giving their own version of events" about Bloody Sunday to the inquiry.
"I also have evidence that a senior IRA man in 1972 was asked recently, after McGuinness announced that he was going to give evidence, to meet a third party. He was then questioned by Raymond McCartney about his intentions and basically told to keep quiet," she said.
The inquiry into the killings by paratroopers of 13 civilians in the Bogside on Bloody Sunday in January 1972, resumed its hearings in Derry yesterday, having spent the last year hearing military, political and other witnesses in London.
Ms Johnston said many of the sources for the book still lived in republican areas and that claims by Mr McGuinness and Mitchell McLaughlin, Sinn Féin's national chairman, that their sources were "all dissidents" who were "riddled with informers" was an attempt to demonise them.
"While it is true that we did interview some people who expressed dissident sympathies during the course of our research, we also interviewed mainstream republicans, including at least two Sinn Féin councillors, political opponents, republican sympathisers, former IRA members, internees, individual members of the security forces, victims of the IRA, nationalist and unionist politicians, as well as politicians in the Republic of Ireland and former Conservative and Labour Secretaries of State for Northern Ireland", she said.
The witness said Mr McGuinness's criticism of the book would "be perceived as an implied threat to our sources" and added that the identification of her sources as dissidents or informers "is a sinister attempt to discredit and demonise them", she said.
"The IRA response to 'informers' is to kill them," said Ms Johnston.
Meanwhile the witness agreed with Mr McGuinness's solicitor, Mr Barry McGrory, that in 1976 she had joined the Workers' Party, which Mr McGrory said was "inextricably linked to a paramilitary organisation", the Official IRA.
She also agreed that "at certain stages" the Provisional IRA and Official IRA "were vehement opponents of each other".
Mr McGrory said that Ms Johnston's political background "predisposes her to be politically against Martin McGuinness", but the witness replied that she and her husband made every effort to contact Mr McGuinness about the book.
"We would have reported him fairly and in fact if we had had the opportunity to put the allegations which were put to us and which we report in our book to him, we would, in fairness, have had to report his answers", she said.
The witness said that one of the sources for the book was former IRA and INLA man Paddy Ward, who during his recent evidence to the inquiry alleged Mr McGuinness had planned to use the Bloody Sunday march as cover for a nail-bomb attack in the commercial centre of Derry.