Mr Justice Barron, head of the independent commission of inquiry into the 1974 Dublin and Monaghan bombings, is to meet the author Mr Don Mullan, who has written a book on the subject.
Mr Mullan provided the inquiry with material, including an affidavit from Mr John Weir, a former RUC officer. This named a UDR captain who allegedly provided the explosives and the name of the former RUC reservist on whose farm the bomb was allegedly assembled and which provided the launch-pad for the attack.
Since the four car-bombs exploded in May 1974, killing 33 people and wounding more than 200, there have been allegations that members of the RUC and British security forces colluded with the loyalist perpetrators.
Mr Mullan also handed over to the inquiry intelligence notebooks from Capt Fred Holroyd, who alleged security force and loyalist collusion in the attacks.
Meanwhile, lawyers for relatives of the victims of the bombings are writing to TDs seeking action on the Victims Commission Report, published 19 months ago.
This commission, under the chairmanship of Mr John Wilson, recommended several measures, including setting up trauma teams; a review of the Criminal Injuries Compensation Scheme; acknowledgement payments to victims and their families; and the establishment of a victims' pension. It also recommended the setting up of a commission of inquiry.
Mr Wilson recommended that a high-ranking civil servant be designated to advance these recommendations, and that an outline implementation plan be produced within six months. The group representing relatives, Justice for the Forgotten, is concerned that little progress appears to have been made.
The inquiry commission was set up over a year ago, with the former chief justice, Mr Liam Hamilton, as its sole member. Mr Justice Barron took over from Mr Hamilton, who died last November.
Mr Justice Barron is continuing to gather information in private for his report, which will go to the Oireachtas Committee on Justice, Equality and Women's Rights.
When it receives his report, the committee will hold public hearings as to whether there should be a public inquiry, and, if so, what its terms of reference should be.
Relatives of those who died will attend these hearings, with their legal representatives. They have always sought a public inquiry. It is understood that Mr Justice Barron's inquiries have included interviewing several people in Ireland and overseas.