Miami Showband killings:The identities of the killers of the Miami Showband, who were massacred on July 30th, 1975, were known within weeks to the highest levels in the British government, the Oireachtas committee reported.
The showband, led by Fran O'Toole and then one of the most popular music groups on the island, played its final gig in the Castle Ballroom in Banbridge, Co Down.
In the early hours, the group left the town to head south in a minibus where they were flagged down by a group of armed men near the Border.
Believing it to be an official checkpoint, they stopped. The band's members were told to get out with their hands up.
A few seconds later, there was an explosion, killing two of the armed men. This was followed immediately by gunfire that killed three of the group, Francis O'Toole, Anthony Geraghty and Brian McCoy.
Stephen Travers was badly injured and Des McAlea managed to escape by fleeing across a field in the darkness.
Two serving members of the Ulster Defence Regiment were charged with murder, convicted and sentenced to 35 years, while a third was arrested later and sentenced to life imprisonment.
Mr Justice Henry Barron noted that a former RUC officer, John Weir, alleged the bomb used in the attack had come from a farmhouse at Glenanne which was frequented by British army intelligence.
The Miami case, and others investigated by him, said Judge Barron, "paints a clear picture of collaboration between members of the security forces and loyalist extremists. The inquiry would be shutting its eyes to reality if it accepted that such collaboration was limited to the cases in which collusion has been proven."
By September 1975, the identities of the murder gang was known, judging by minutes of a meeting involving then prime minister Harold Wilson, the Northern Ireland secretary of state, Merlyn Rees, the future British prime minister Margaret Thatcher, and Airey Neave, the Conservative Party spokesman on Northern Ireland, who was murdered by an Irish National Liberation Army car bomb four years later.
The Oireachtas joint committee report concluded: "The secretary of state was more worried about sectarian murders than about the bombings in Belfast, and it was unfortunate that certain elements in the police were very close to the Ulster Volunteer Force and prepared to hand information to, for example, Mr Paisley. It [ the minutes of the meeting] states the army's judgment was that the UDR was heavily infiltrated by extremist Protestants who could not be relied upon to be loyal in a crisis. The regiment which could not be relied upon in a crisis was mobilised in south Armagh in the wake of the attacks at Donnelly's Bar, Kay's Tavern, on the Reavey and O'Dowd households and the Kingsmills massacre," the joint committee report said.