Senior gardai are to review the files on the death of a 20-year-old soldier in the Lebanon.
Private Kevin Barrett was found dead with a single gunshot wound in his army billet in south Lebanon in 1999.
An independent report into the three investigations carried out by the military police, the Irish army and the UN found that serious questions remained unanswered about how the Donegal man had died.
Its author, the former Ombudsman Sean Hurley, recommended the involvement of the gardai in the investigation.
"The Garda might be requested initially if they have jurisdiction in this matter and if so what the likelihood was of a successful investigation," he said.
A spokesman for the Minister for Defense Willie O'Dea confirmed that he would be making the investigation files available to gardai at the earliest possible opportunity.
Private Barrett had been drinking in the early hours of February 18 1999 and was in his billet with two other soldiers when the fatal shot was discharged.
A military police investigation by Sergeant John O'Neill found that the shooting appeared to be accidental but highlighted a number of unexplained areas.
These included the three holes found in the front wall of the billet, how Private Barrett's weapon ended up in the billet, how it was loaded and how it was discharged.
The scene of the shooting was not preserved by the army and the fatal bullet shell went missing.
Mr Hurley found that there was no evidence that the Irish army considered Sergeant O'Neill's recommendations to carry out a further investigation into the death, to involve the Gardai or to conduct further interviews with one of the soldiers in the billet.
He said the two further reports, which were carried out by an Irish Contingent Board of Enquiry and a United Nations Headquarters Board of Enquiry, relied entirely on Sergeant O'Neill's first report.
"The Investigating Officer raised serious concerns about his investigation which were not properly addressed. As a consequence, his investigation was technically incomplete. In my view it does not constitute an effective investigation."
Helen Barrett, who campaigned for seven years for an explanation for her son's death, said Sergeant O'Neill had wanted a thorough job done but no heed was paid to him.
"It's what I expected all along. There wasn't really a proper investigation done on Kevin's death at all," she said.