A book on the McGurk's bar bombing could shine new light on the 1971 massacre, it has been claimed.
Author Ciaran MacAirt, whose grandparents were among 15 people killed when the no warning bomb ripped through the north Belfast pub exactly 41 years ago, said he hoped the publication would help the families' quest for justice.
Speaking ahead of a launch at Stormont, Mr MacAirt said: "This not only gives us the opportunity to engage with politicians directly, it also makes them aware that even after 41 years the families have fought and are having to continue to fight to clear the name of their loved ones."
The attack on McGurk's on December 4 1971 was the worst atrocity of the Troubles until the 1998 Omagh bomb in which 29 people died. Three women and two children were among those killed at McGurk's, and 16 people were injured.
Shortly after the explosion, then Stormont home affairs minister John Taylor said he believed the IRA was responsible. In 1978, UVF member Robert Campbell was convicted of his part in the attack.
Mr MacAirt said: "The book has gathered not only evidence that has been produced by the Police Ombudsman and the (PSNI) Historical Enquiries Team but also documents and articles that I, the Pat Finucane Centre and that British Irish Rights Watch have found."
Last year the Police Ombudsman found there had been no collusion between security forces and loyalist paramilitaries but Al Hutchinson's report concluded there was investigative bias towards blaming republicans.
On Wednesday the victims' families are expected to take their campaign to London where West Belfast MP Paul Maskey will host an event at Portcullis House, Westminster.
Mr Maskey said: "It is important, given the history of the propaganda put out by the RUC and British media at the time that the bombing was carried out by the IRA and the lack of investigation by the RUC into the bombing, that we get to the truth."
Colin Wallace, who was a senior Army information officer on duty at the time of the bombing, is expected at Westminster. Mr MacAirt said: "He will tell, as he writes in the book, that all reports were that it had been a loyalist bomb and that was still the case when he went off duty."