As the Minister for Justice says in his report published yesterday, people involved in an attempt to suppress evidence in the 1970 Arms Trial were "highly unlikely to leave evidence about which would demonstrate their involvement or their intent".
Having said that, both he and the Attorney General have concluded that the likelihood of such a conspiracy is remote. They have found no documentary evidence pointing to it. Both lament the fact so many people who could cast light on what happened are dead.
As a result, says Mr McDowell, "it is simply impossible to come to water-tight conclusions of fact or to make wholly reliable calls on the issues that call for value judgment".
Both Mr O'Donoghue and Mr McDowell examined documents relating to the editing of a statement by Col Michael Hefferon, former head of Army intelligence. The editing cut out references suggesting the then minister for defence, Mr Jim Gibbons, knew of and approved the plan to import arms.
The significance of this information is that that if the minister for defence approved the plan, it could not be said to be illegal, and therefore the case against the four accused would have been undermined.
The Attorney General's report confirms that Col Hefferon's Garda statement was "extensively edited before being included on the Book of Evidence served on the accused". However it was, and is, usual practice to edit statements "to exclude, for example, hearsay and irrelevant material".
Nevertheless, he says, Col Hefferon's statement could be said to have been made to look more compatible with the line taken by Mr Gibbons in his statements to the gardai. The controversial edited version of Col Hefferon's statement was probably prepared by gardai in Dublin Castle, he says, under the supervision of some or all of three prosecution lawyers, Mr Edward Durnin, of the Chief State Solicitor's Office, Mr Aidan Browne BL and Mr Declan Quigley of the Attorney General's office.
He says he cannot entirely exclude the possibility that these lawyers consulted with third parties. "But there is no shred of evidence that there was any outside consultation or influence."
Suggestions that a claim of privilege was used as part of a conspiracy to keep the prosecution lawyers in the dark also "seem to be wide of the mark", he says. Certificates of privilege signed by the then minister for justice, Mr Des O'Malley, on day two of the second Arms Trial contemplated production of the documents in question to the trial judge, he says. "That would hardly have been done if one of the documents had been deliberately altered to deceive the court."
Mr Des O'Malley issued the following statement last night:
"I welcome the reports of the Minister for Justice, the Attorney General and the Garda Commissioner in respect of questions relating to the Arms Trial. It is clear from these reports that:
The changes made to the Hefferon statement were properly made by members of the prosecution legal team in conjunction with the investigating gardai. It seems that these changes were made primarily in order to comply with the rules of evidence.
Neither I nor Mr Berry had any involvement with such changes.
The claim of privilege was made on foot of legal advice and the certificates of privilege themselves were drafted in the Attorney General's office.
These three reports are perfectly compatible with my earlier statement of May 9th, 2001