A former detective sergeant has denied he betrayed his oath and his colleagues but acknowledged that he failed to pass on information about an IRA ambush in which two RUC officers were killed.
Owen Corrigan also said that he was not asked by senior officers about rumours which had been circulated he was assisting the Provisional IRA because, he said, they did not believe them.
Mr Corrigan, along with former sergeants Leo Colton and Finbarr Hickey, is being examined by the Smithwick Tribunal to see if any of them colluded with the IRA in the killing of two senior RUC officers.
Chief Supt Harry Breen and Supt Bob Buchanan died in an IRA ambush as they crossed the border back into Northern Ireland in March 1989, just minutes after leaving a meeting in Dundalk Garda Station.
Counsel for the Police Service of Northern Ireland, Mark Robinson, continued his cross examination of Mr Corrigan on evidence he had previous given to the Tribunal.
Earlier, Mr Corrigan said he had got information after the ambush that the two RUC officers had been followed for several weeks previously.
On another occasion as they entered Dundalk Garda Station, the leader of the IRA in South Armagh walked in behind them.
He had also been told that the ambush in which the two men were killed was planned since January 1989 and that a previous IRA operation had missed the RUC men by a matter of minutes.
This intelligence came from a reliable source, he said.
Mr Robinson asked Mr Corrigan what he did with that information as it was not contained in garda intelligence reports known as C77s.
In fact, he said, Mr Corrigan did not submit any C77s in the immediate aftermath of the shooting.
The witness acknowledged that perhaps he should have filed reports with this intelligence.
It was put to him that this was vital information that could potentially have given a lead to the investigation into the ambush to which Mr Corrigan replied "that is speculation."
It was also put to him that he had this intelligence while the investigation into the ambush was under way and he accepted that was the case.
Asked why he had waited until 2012 to reveal this information, the witness replied that he did not really know.
Mr Robinson also raised the issue that Mr Corrigan did not file any intelligence reports noting increased activity in advance of the ambush even though a large number of people were involved and Mr Corrigan was the "jewel in the crown" of investigating gardaí.
It was put to the former detective sergeant that good intelligence is often collected in the immediate aftermath of an attack either by people talking or by watching certain people.
However, he accepted he did not get involved in any of that as he finished work shortly after the ambush.
Mr Corrigan said he was not asked to stay nor was anyone else but acknowledged that he did not volunteer either.
He also did not file any C77s in the immediate aftermath of the ambush although his counsel, Jim O'Callaghan, pointed out he did file some in July of 1989 naming those he believed were involved in the attack.
Mr Robinson accused Mr Corrigan of betraying his garda oath, his colleagues and the two RUC men by failing to act. However, the former detective sergeant strongly disagreed and said he did not betray anyone.
Mr Corrigan was also asked about the rumours he was working for the IRA.
He said that was misinformation put about by the republicans to try and discredit him because he was such a thorn in their side and to allow them to "collect the British shilling from the Crown."
He also said that no senior officer had come to discuss rumours about his financial affairs or about possible collusion with the IRA.
Mr Corrigan said this was because they were far too experienced to have believed these false rumours.
He said the RUC had no concerns because they were meeting gardaí every month and never said anything.