Former sergeant Thomas Byrne said that although he had information to give about a former sergeant represented before the tribunal, his name had not been passed to the inquiry.
Mr Byrne said that in 2009 he wrote to the Garda commissioner about “a conspiracy to pervert the course of justice” involving serving gardai, and said he had a tape recording which would prove his allegations.
In the letter, he referred to incidents when he was a sergeant in Dundalk, as an illustration of the reluctance of gardai to speak out against each other.
And he said that although he had knowledge about events in Dundalk which the Garda were aware of, he had not been contacted by the Smithwick tribunal, “demonstrating that co-operation with the tribunal was not all that it might have been.”
“No one informed the inquiry I had evidence possibly of value,” Mr Byrne said.
Mr Byrne said there was “a great reluctance to take on each other” within An Garda Siochana.
Mr Byrne said that when he was a sergeant in the border station of Dundalk, other officers came to him with concerns about another sergeant, Leo Colton, “some with subversive connotations.”. Eventually, he wrote out the allegations on a blackboard in the parade room in Dundalk garda station.
He said that after the board was rewritten and erased two times, he was told by a senior officer that sergeant Colton was “very well connected within the force, his brother is a chief superintendent.”
The allegations written on the blackboard included a shoplifting incident, the removal of money from a meter in a snooker room in the garda station, two items which Mr Byrne said he was “not allowed to mention” during a public hearing, the use of a garda patrol car in cross-border smuggling, the misappropriation of a file from garda records, information from that file passed on to the subject of a planned investigation, and “taking advantage of women when they were reporting problems”.
Mr Byrne also said that sergeant Colton spent a lot of time in the tax offices next door to the Garda station, but he did not know what he was doing there.
The former sergeant agreed with Mr Eamon Coffey, representing Mr Colton, that he had no personal knowledge of wrongdoing, only hearsay and rumour told to him by other officers.
And he said although the money missing from a meter in the snooker room was investigated by another garda, Vincent Rohan, who found that sergeant Colton was responsible, no charges or disciplinary action was taken.
“Vincent Rohan would be a better person to ask that question of than me,” he told judge Peter Smithwick.
The tribunal is looking at claims that a garda tip-off allowed the IRA to set up an ambush in which chief superintendent Harry Breen and superintendent Bob Buchanan died on 20 May 1989, as they returned from a meeting in Dundalk Garda station.
Former garda sergeants Leo Colton, Owen Corrigan and Finbarr Hickey deny they ever leaked information from the Garda Station.