Gardaí believed they had the right to collect information from suspects by secretly taping conversations they had while in custody, a former detective sergeant has told the Morris tribunal.
John White has alleged that privileged conversations were covertly recorded during the investigation into the death of cattle dealer Richie Barron, a hit-and-run victim.
Garda Tina Fowley told the tribunal that she was present when senior officers discussed obtaining support from the Garda technical section to see if any information could be gleaned for the investigation.
Joe Costello, a retired Garda electronics specialist, told the tribunal he had no knowledge of the bugging of prisoners' conversations with visitors or solicitors during the Garda investigation.
Mr Costello said he had only recorded a prisoner's conversation once in his 30-year career, when he was asked to tape two prisoners in a cell in Ballinasloe during a murder investigation in the early 1990s.
The tribunal heard that one man was convicted and another vindicated as a result of the recording, which was disclosed to the defence at trial.
Mr White said although he had not heard about the Ballinasloe case until Tuesday, gardaí "believed they had a right" to record suspects during criminal investigations.
Mr White said Mr Costello could not admit that covert taping of suspects occurred, because it "would open up a huge vista" and could lead to cases against the State for breaches of constitutional rights, and overturned convictions.
However, Mr Costello again insisted he told the truth to the tribunal in his evidence.
Mr Costello said he "was on standby duty" in Co Donegal on December 4th, 1996, and this was why he had claimed overtime while in Letterkenny, even though he had done no work there.
"You were looking after the taping system that was in place," Mr White said.
"I have no knowledge of any taping," Mr Costello said. "I was asked to stay there, and I stayed."