The Garda investigation into the death of Donegal cattle dealer Richie Barron was prejudiced and negligent and two men were framed by gardai for his murder, the Morris Tribunal has found.
The Minister for Justice Michael McDowell said the report's conclusions "are extremely serious, at times shocking".
The report found the investigation into the hit-and-run in which Mr Barron died in October 1996 near Raphoe, Co Donegal was lacking from the outset and was a "justifiable cause of scandal".
He found the gardai were so slow to respond to the emergency call in which the Barron incidnet was reported, that the body had been removed to Letterkenny General Hospital before they arrived at the scene.
Contrary to required practice, the scene was not preserved and the body or clothing of Mr Barron was not preserved at the hospital. In this respect the gardai were "hopelessly negligent", Mr Justice MOrris said in the report.
Other criticisms included the failure to make inquiries locally immediately after the accident and the subsequent investigation was also found to be lacking.
"Conferences in the Barron inquiry were not properly noted, jobs books are chaotic and several important books have pages missing. Some conferences were not even the subject of a note as to who was present," Justice Morris says.
One of the most serious criticisms of the investigation was the failure to order a forensic post mortem after the standard procedure was carried out at the hospital.
Despite this, a murder inquiry was launched based on the word of a local informer who, the tribunal found, had been coerced into making a statement against local man Mr Frank McBrearty Jr and his cousin Mark McConnell.
"As a direct result of mismanagement and misconduct on the part of a number of the members of the Gardaí involved in the investigation, these two suspects were wrongly considered to have been responsible for Mr. Barron's death," Mr Justice Morris found.
The informer, Robert Noel McBride, was described by Morris as a "man of suggestible mind".
Justice Morris said: " After the fullest possible consideration, I am reluctant to make a finding that the investigation was corrupt in its leadership. It was prejudiced, tendentious and utterly negligent in the highest degree.
"Chief Superintendent Denis Fitzpatrick, Superintendent John Fitzgerald, Detective Superintendent Joseph Shelley and Detective Inspector John McGinley all share in various degrees the burden of fault for this matter."
Mr McDowell characterised the report as finding "elements within the Garda Síochána who set out to frame Frank McBrearty Junior and Mark McConnell for murder".
"While the report is reluctant to make a finding that the investigation was corrupt in its leadership, it finds that it was prejudiced and negligent in the highest degree," Mr McDowell said.
He also revealed that publication of the report had been brought forward because a member of the media has gained unauthorised access to the Tribunal's web server, "improperly" obtaining a copy of the report.