The judge in the Omagh bomb trial turned down an application yesterday to have two of the charges against Sean Hoey dismissed because of a police conspiracy to bury evidence.
Mr Justice Weir branded the actions of two detective sergeants "reprehensible" and said their credibility had been brought into serious question.
Yesterday the defence team for the 37-year-old south Armagh man claimed there had been "a unity of purpose, otherwise known as a conspiracy" by police to "bury" evidence.
They applied for two of the 58 charges faced by the accused, which are unrelated to the Omagh bombing, to be dismissed.
The charges concern a murder conspiracy and a mortar bomb discovery at Altmore Forest at Dungannon, Co Tyrone, in April 2001.
Mr Justice Weir told defence counsel Orlando Pownall QC that he was refusing the application.
However, he described the actions of Det Sgt Fiona Cooper and Det Sgt Philip Marshall, now promoted to chief inspector, as "reprehensible". He said the defence had exposed false and misleading evidence.
The judge went on: "I do not, however, accept in the course of the present case that the conduct of the police witnesses is so grave as to threaten or undermine the rule of law itself."
The accusations against the two police witnesses centred on their written statements that had replaced earlier statements, which had since disappeared.
No mention of the original statements had been made in the case until Mr Pownall had discovered that what was before the court was in fact a pair of substitute statements.