The RUC officer in charge of the investigation into the August 1979 Warrenpoint ambush in which 18 British soldiers and one civilian were killed arranged for a meeting between the two most senior police officers in Ireland in a bid to complete his investigation.
The officer, identified as Witness 68 at the Smithwick tribunal, gave evidence from Belfast by video link because of ill-health.
Witness 68, who retired in 2001 with the rank of deputy assistant chief constable, was a detective inspector at the time of the lethal attack.
He said he liaised with the then RUC chief constable, and got him to meet with the Garda commissioner.
There was “a degree of reticence” in the cooperation between the two forces following the Warrenpoint attack, he said, although relations were “more congenial at local station level”.
The witness was also asked about a meeting at the time involving the taoiseach, but did not answer this question following objections from other lawyers.
Barristers for the garda commissioner said they had not been given instructions on the issue, and asked that the evidence be given at a later date.
Tribunal chairman Mr Justice Peter Smithwick said he was “very anxious that the witness should be allowed to give his evidence as he sees fit”, and agreed the topic would be revisited on a later date.
“I hope that you will be able to speak the untrammelled truth as you see it, that is what this tribunal is about,” he told the witness.
The witness said that later in his career he worked with three garda commissioners, PJ Culligan, Pat Byrne and Noel Conroy, and found them “exemplary, professional, and very good detectives.”
But he slammed the lack of cooperation from An Garda Siochana following the Warrenpoint bombing.
The tribunal has previously heard that a detonation site for the two bombs on the southern side of the border was “obliterated” before RUC forensics officers could examine it.
RUC officers visited the scene late in the evening a few days after the bombing, but when they returned the following morning the area had been cut with a scythe.
“The cutting of the scene was something that to a detective of my experience was totally and completely inexplicable,” Witness 68 said.
The witness said the forensic scientist who visit the scene was “world renowned”, and had consulted with several police forces, including An Garda Siochana.
“The word I would use to describe him is enraged,” he said. “I myself was furious.”
“There was a promise that the scene would be preserved, that was why we went to the trouble of bringing a forensic team from Belfast.”
The witness said the senior investigating officer on the southern side of the border was detective sergeant Owen Corrigan, and the site could not have been cleared without his knowledge.
And he said he was briefed by an RUC detective superintendent that Mr Corrigan was”a risk.”
“I was told it at the scene of the Warrenpoint explosion when the senior officers were gathered together,” he said.
The witness will continue his evidence at a later date.
The tribunal is investigating allegations of garda collusion in the IRA ambush which killed two RUC officers in March 1989. Mr Corrigan denies allegations of collusion, describing them as a “monstrous lie”.
At the close of his evidence, the tribunal chairman expressed his condolences to the family of the late Mr Thomas Reid, a retired RUC officer. Mr Reid had been scheduled to give evidence at the tribunal today [28 February].