Image caption
Harry Breen and Bob Buchanan were murdered by the IRA in 1989

The Smithwick Tribunal examined suggestions that members of the Irish police or other employees of the Irish state colluded in the murders of the two most senior RUC officers to die during the Northern Ireland Troubles.

20 March 1989: RUC Chief Supt Harry Breen and Supt Bob Buchanan are murdered by the IRA in an ambush on the Edenappa Road, near Jonesborough in south Armagh, near the Irish border. They were returning from a meeting at Dundalk garda station in the Republic of Ireland.

21 March 1989: Press reports the following day speculate about a 'mole' in Dundalk Garda station.

22/23 March 1989: Assistant Garda Commissioner Edward O'Dea prepares a report into the circumstances of the RUC officers' meeting in Dundalk Garda station. He finds no evidence of collusion.

November 1999: Journalist Toby Harnden's book, Bandit Country: The IRA and South Armagh, is published. In it, he alleges collusion between Garda X and Garda Y in Dundalk and the IRA.

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The men were targeted on their way back from a meeting at Dundalk Garda Station

10 March 2000: Journalist Kevin Myers publishes an article in the Irish Times repeating the allegation of collusion.

25 March 2000: Ulster Unionist leader David Trimble writes to the then Irish prime minister, Bertie Ahern, calling for an inquiry.

13 April 2000: MP Jeffrey Donaldson makes a statement in the House of Commons alleging that Garda X is former Dundalk Detective Sergeant Owen Corrigan.

13 April 2000: TDs Charles Flanagan and Jim Higgins ask questions in the Irish parliament about collusion allegations. In the following months, Garda Commissioner Pat Byrne instigates an investigation. Chief Supt Sean Camon and Inspector Peter Kirwan report on the collusion claims and find no evidence to support them.

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Chief Supt Breen was the highest-ranking member of the RUC to be killed by the IRA. He was survived by his wife and two children

March 2006: Private investigation phase of the Smithwick Tribunal begins. Judge Smithwick says the inquiry will investigate whether there was collusion in the "widest sense of the word" - that means he will also consider whether there was a failure to act to prevent the two officers being murdered.