Two former detectives clashed at the Morris tribunal on its 600th day over allegations that confidential meetings were secretly recorded by gardaí in Donegal.
John McGinley, a retired detective superintendent, has said the allegation that he was seen listening to tape-recordings of confidential conversations between prisoners and their solicitors in Letterkenny Garda station during the investigation into the death of cattle-dealer Richie Barron was "ridiculous" and "absurd".
Mr McGinley was questioned by John White, a former detective sergeant, who is representing himself at the tribunal.
Mr White has alleged that privileged conversations were covertly recorded during the investigation into the death of Mr Barron, a hit-and-run victim, on the day eight people were arrested, including cousins Frank McBrearty jnr and Mark McConnell. Mr White alleged that he saw Mr McGinley listening to some of the tapes on the day of the arrests.
Retired garda John Dooley has also said he was with Mr White and former Garda electronics expert Joseph Costelloe when they talked about bugging the station.
Mr McGinley said it was logistically impossible for him to have been in the inspector's office in Letterkenny at the time when Mr White said he saw him listening to a tape-recording of a conversation between a prisoner and her solicitor. He said he was on a meal break at the time Mr White said the incident happened, and was not an inspector at the time, and the detective inspector's office had been used as an interview room that day.
Mr McGinley said there had been no conference at 6pm that day to discuss progress in the various interviews, as alleged by four members of the National Bureau of Criminal Investigation (NBCI). He said that after he finished an interview at 6pm he did recall going to the incident room, and there were people there, but he did not remember "any formal setting as such".
The four NBCI detectives say the 6pm meeting was told Frank McBrearty jnr might be willing to make a statement.
Mr McBrearty denies he made any admission in Garda custody.