Colm Murphy was finally tracked down after painstaking detective work by security forces on both sides of the Border traced the paths of four mobile phones used in the Omagh bombing.
The court heard that two of those mobiles were supplied by Murphy to the bombers while two others were "Ready to Go" mobile phones - phones bought over the counter which are untraceable.
Murphy used his own mobile phone, which he told gardaí he had owned for about four years, and also borrowed a Nokia mobile from one of his unsuspecting workers - bricklayer Mr Patrick Terence Morgan, from Cullyhanna in south Armagh.
Mr Morgan, Murphy's second cousin and an innocent party to the whole affair, told the court on November 14th last year that Murphy asked him on the day before the Omagh bombing if he could borrow his mobile as his own wasn't working. The conversation took place on the site at Dublin City University in Glasnevin, where Murphy had one of his lucrative contracts.
Mr Morgan agreed and his phone was returned to him on the Monday or Tuesday of the next week without him realising what it had been used for.
Mr Morgan was subsequently arrested by the RUC, who raided his home and seized his mobile phone. Then, in a dramatic turn when the trial resumes after the Christmas break on Friday, January 11th, Mr Morgan returned to the witness box and retracted his earlier evidence.
He told the court that he had been put under pressure by gardaí to give evidence and he now denied giving his mobile phone to Murphy. He said that his phone "went missing" from his van on Friday, August 14th and he found it under the seat on the following Monday. "I did not lend the phone to anyone and I did not give it to anyone," he said.
The two mobile phones given by Murphy to the bombers were later tracked on the day of the Omagh bombing - Saturday, August 15th, 1998.
The pattern of the calls revealed the journey gardaí believe the bombers took on that fateful day.
The first call was made from the mobile phone Murphy had borrowed from Mr Morgan and was to Murphy's own mobile phone, then being used by the bombers.
The call was at 2.09 p.m. and was picked up by the mobile phone mast at Bridge Street in Omagh.
The second call was at 2.14 p.m. and was to a Ready to Go phone and was handled by the Northern Ireland Electricity Board's pylon tower at Pigeon Top, Mount Pollnaghunt, Co Tyrone.
The next call was at 2.19 p.m. and was to Murphy's phone and was picked up by the Pigeon Top tower.
At 3.41 p.m. there was a call to another Ready to Go mobile which was handled by a mast at Clontibret, Co Monaghan.
At 4 p.m. a call was made to Murphy's phone and picked up at Castleblayney, Co Monaghan. There was a call at 4.01 p.m,. again to the Murphy phone, and picked up at Tallanstown, Co Louth.
The final call was at 5.30 p.m., was to a Ready to Go phone and was picked up at Dundalk. All the calls were brief.
The pattern of calls from Murphy's phone to the phone borrowed from Mr Morgan again revealed a pattern to investigators.
The first was at 12.41 p.m. and was picked up at Castleblayney. The second call was at 1.13 p.m. and was picked up at Emyvale, Co Monaghan.
The third call was at 1.29 p.m. and was picked up at Aughnacloy, Co Tyrone, and the fourth call was at 1.57pm, and was handled by the mast at Bridge St in Omagh. Twelve minutes later, at 2.09pm, the Morgan phone was also at the same location.
A fourth call from the Murphy phone to the Morgan phone at 3.13 p.m. and was picked up ay Monaghan town.
A fifth call at 3.30 p.m. was made to another person unconnected with the incident. Again, all calls were brief.
The first bomb warning was received at 2.34 p.m. and the bomb in Omagh detonated at 3.05 p.m.
Investigators also traced the pattern of calls made from Murphy's phone on August 1st, 1998 - the day of the Banbridge bomb.
Calls were recorded at 1.40 p.m. and 1.48 p.m. and picked up by the mast at Ravensdale, Co Louth.
At 1.51, a call was picked up by a Co Louth mast and at 2.09 p.m. a call was picked up at Dundalk. At 2.18 p.m. a call was picked up at Co Louth, at 2.19 p.m. a call was made again at Co Louth.
A call was made at 2.44 p.m. and picked up in Co Louth, and at 2.48 p.m. a call was picked up in Co Louth. The last call was at 16.48 and picked up at Ravensdale.
The record of calls received on the Murphy mobile the same day showed that four were made from Banbridge or near Banbridge at 3.39 p.m., 3.42 p.m., 3.48 pm and again at 3.48 p.m. The bomb at Banbridge detonated at 4.31 p.m.
The pattern of calls made on Murphy's mobile phone led gardaí to the conclusion that he had played an important role in helping the "Real IRA" bombers.
Close co-operation between the RUC Criminal Investigation Department and a Garda team based at Monaghan eventually led to the decision to arrest Murphy and during questioning at Monaghan Garda Station in February 1999, he made the admissions which led to his conviction.
Det Garda James B. Hanley, one of the most experienced interrogators in the Garda, told the court that when Murphy was asked if he knew his phone was going to be used in a criminal act, Murphy said: "Yes, I knew it would be used for moving bombs. I knew these fellas were involved in moving bombs to Northern Ireland to bomb targets."