Brief details of a meeting between the former IRA leaders and the Smithwick Tribunal’s legal team were revealed during the first substantive public hearing of the tribunal since it was established in 2005.
In an opening statement, tribunal barrister Mary Laverty SC described the meeting as “a very significant development”.
The tribunal is investigating claims that one or more gardaí colluded with the IRA by passing on information that RUC officers Chief Supt Harry Breen and Supt Bob Buchanan were in Dundalk Garda station on March 20, 1989.
Both were killed in an IRA ambush just north of the border, near Jonesboro, Co Armagh, as they returned from Dundalk.
Ms Laverty said one of the IRA representatives who met with the tribunal was in charge of the operation to murder the RUC officers.
However, she did not disclose any more detail about the information supplied by the former IRA members.
Ms Laverty named three former gardaí — Owen Corrigan, Leo Colton and Finbarr Hickey — as being suspected of collusion with the IRA at various stages.
All three men reject all allegations of passing on information to the IRA.
The tribunal heard that Chief Supt Breen expressed concern on the day of his murder about Mr Corrigan being in the pay of the notorious republican leader, Thomas “Slab” Murphy.
Ms Laverty said its inquiry team was repeatedly told by former RUC officers that there was concern about Dundalk Garda Station during the 1980s.
She said the tribunal had received intelligence suggestive of collusion, but equally evidence showed that the Provisional IRA could have carried out the operation without any assistance from gardaí.
The tribunal will also examine rumours that the IRA learned of the RUC officers’ movements by tapping telephones at Dundalk Garda Station.
Sinn Féin president Gerry Adams confirmed yesterday that the tribunal had sought the party’s help to make contact with the IRA.
While Sinn Féin said there could be no engagement with the IRA as it had “left the stage” in July 2005, he said the party had facilitated the tribunal by establishing that former IRA members were willing to engage with the inquiry on a voluntary basis.