A retired detective sergeant said that interview notes taken while questioning a man for murder were not read over and signed because the prisoner had to be released from Garda custody.
Pat Hennigan said the interview came to a sudden end when Garda Martin Leonard told officers their time was up and Mark McConnell had to be released.
Mr McConnell and his cousin Frank McBrearty jnr were wrongly arrested for murder in December 1996 during the Garda investigation into the death of hit-and-run victim Richie Barron. The tribunal has found both men were innocent.
"Martin Leonard came in and said 'time's up boys', or something to that effect. There was no more time," Mr Hennigan said. The detective had entered the room where Mr McConnell was questioned 40 minutes before his release.
Three sets of interview notes from the arrest have gone missing, Peter Charleton SC, for the tribunal, said.
"Something very strange is going on here," the chairman, Mr Justice Frederick Morris, said.
"Everybody is acting in an unusual way and nobody can fill me in on the picture. I'm finding it very trying. You don't know why you were put in, you don't know why he was sent out, you don't know who told you to go in, you don't know whether they were taking notes when you went in or not, you don't know why the notes weren't signed afterwards."
Mr Justice Morris continued: "You say that he was rushed out so quickly there was no forewarning that he was going, that's why they weren't read over to him and you don't know why you didn't sign them. And you all went home and no one is giving me any explanation for this unusual behaviour."
Mr Hennigan said he could not remember who told him to go into the interview room or why he had to relieve a detective who was in the room.
Another retired detective sergeant, James Leheny, told the inquiry he had handed in the interview notes he took into the incident room, but they had since been mislaid.
"I don't know if the notes were handed in to the incident room or not," Mr Hennigan said, adding that Det Sgt Leheny would have taken notes during the interview. "He has the reputation of being very thorough on paper. I couldn't see him conducting an interview without taking meticulous notes."
He said he did not hear Mr McBrearty shouting or yelling in Letterkenny Garda station at any time during the arrests. "Maybe I wasn't in the right place. With the exception of Mark McConnell, I don't know where the other people were when they heard him yelling."
Mr Hennigan also said he was not aware of a document written by Garda Martin Leonard, until it was produced at the tribunal, in which he listed a series of complaints made by Mr McConnell's solicitor, he was not aware of postmortem photographs being shown to Mr McConnell, and Insp John McGinley had not shown Mr McConnell a purported statement from Mr McBrearty while he was in the interview room.