A judge in Dublin has directed that a not guilty verdict be found in the trial of two Irish police officers.
Twenty nine people died in the Real IRA attack
Liam Donnelly and John Fahy were charged with perjury during the trial five years ago of Colm Murphy on Omagh bomb conspiracy charges.
However, the judge said evidence against the men was inadmissible.
Mr Murphy's conviction and 14-year jail sentence was quashed last year after the Appeal Court found the evidence of the two gardai was unreliable.
He faces a retrial next year.
Mr Murphy was charged with conspiracy to cause the Omagh bomb.
The evidence against him was substantially based on the alleged use of his mobile phones by some of the bombers.
At his trial in 2001 and in 2002, the Special Criminal Court in Dublin heard evidence from experts called by Mr Murphy's defence who examined interrogation notes using electrostatic document analysis and said that those taken by Detectives Fahy and Donnelly had been altered.
The tests concluded that a different page had been added to their notes.
The two detectives swore on oath that they did not alter the interview notes, but the judges at Mr Murphy's trial concluded that the detectives had altered the notes and said they had lied in court in their evidence.
However, at Monday's hearing, both Mr Donnelly and Mr Fahy were found not guilty of two counts of perjury and were also acquitted of two counts of forging notes of interview with Mr Murphy.
Delivering his verdict the judge said that the prosecution had been unable to establish a chain of custody in relation to the original notes of interview or of the later electrostatic document analysis.