The pathologist in Letterkenny General Hospital who examined the body of Mr Ritchie Barron said he now considered it was probable his injuries were caused by a vehicle.
Following his initial examination in 1996, Dr David Barry told gardaí Mr Barron's injuries were likely to have been caused by being struck with a blunt instrument.
"I feel the additional forensic evidence shifts the balance of probabilities significantly towards vehicle impact. Assault cannot be ruled out; that awaits further investigation," he told counsel for the tribunal, Mr Peter Charlton SC.
He said he was a fellow of the Royal College of Pathologists, but was not trained as a forensic pathologist. He agreed with a statement from the State pathologist, Dr John Harbison, that a forensic examination would have gone further than a normal post-mortem.
He said he was not told of a missing piece of Mr Barron's scalp being found at the scene until four years later. This strongly suggested a traffic accident. He accepted scraping at the front of the skull, discovered by Dr Harbison following an exhumation, also indicated the likelihood of a traffic accident.
Garda Patrick Boyce told Mr Paul McDermott SC, also for the tribunal, he was not covering up for colleagues in not giving a full account of his attempts to get gardaí to the scene of Mr Barron's death when these events were the subject of an internal Garda inquiry.
He was the communications officer on duty in Letterkenny district headquarters that night, and he said he received a call from Ms Hilary McBride that Mr Barron was lying seriously injured on the road at Townparks, Raphoe, following an accident. He tried unsuccessfully to contact Garda Padraig Mulligan in Raphoe by radio but there was no response.
He then contacted Lifford station, where he spoke to station orderly Garda P J McDermott.
Garda McDermott said the two gardaí there were on their meal break. He also insisted that there was no Townparks in Raphoe, and suggested the caller meant Townparks in Convoy. Garda Boyce then asked gardaí in Ballybofey to go to Convoy.
Ms McBride called back asking why no one had arrived at the scene where Mr Barron was lying injured. He then phoned Lifford again, and asked them to go to Townparks in Raphoe.
"Was there any argument then as to whether Townparks existed or not?" asked Mr Justice Morris.
"No," he replied.
Asked about procedures for dealing with a situation where there was a possibly fatal traffic accident, he said he would contact a sergeant or the senior member working.
"Are you of the opinion that life would not be worth living if you contacted a senior officer about a fatal road traffic accident," asked Mr McDermott.
"You might get a quick answer," the garda replied.
Asked why he had not given details of his attempts to contact members of the force when these events were being inquired into, he replied: "I did not want to draw attention to members."
He denied this was covering up for members who failed to respond, but agreed they would be embarrassed by the details.
The tribunal continues.