Chief Superintendent Harry Breen and Superintendent Bob Buchanan were on their way home from Dundalk Garda Station when they were murdered in an IRA ambush just north of the border near Jonesborough, south Armagh, on Mar 20, 1989.
In his 500-page report, Mr Justice Peter Smithwick says there “is no record of a phone call, no traceable payment, no smoking gun” but he is satisfied that “on the balance of probability” one or more gardaí supplied information to the IRA.
Tánaiste and Foreign Affairs Minister Eamon Gilmore said the country must confront the grave findings of collusion.
“I am appalled and saddened by this finding. It is a matter of grave public concern,” he said.
“On behalf of the Government and the people of Ireland, I apologise without reservation to the Breen and Buchanan families for any failings identified in the report on the part of the state or any of its agencies.”
Justice Minister Alan Shatter also apologised. “Even with the passage of 24 years and the positive developments which have taken place on the island since, our condemnation of their murder should be as strong today as it was then,” he said.
Mr Shatter said nothing in the report should detract from the good work of An Garda Síochána during the Troubles.
Sinn Féin president Gerry Adams said people “will make up their own minds when they read this report”.
“It is important to note that while the Irish Government has kept its commitment... the British government... is in clear breach of commitments having refused to establish an inquiry into the murder of human rights lawyer Pat Finucane,” he said.
In his report, Judge Smithwick said: “It is particularly regrettable that both police services acted swiftly to dismiss speculation of the possibility of collusion rather than to deal with that by means of a thorough and credible investigation.”
“This was an example of the prioritisation of political expediency in the short term.”
The report confirmed that active service units of the IRA were active on the day in question and were on standby for an anticipated operation, before the arrival of the two officers. Mr Justice Smithwick said it seemed “beyond doubt” that the IRA acquired information that the officers had arrived at the station.