The man gardai believe directed the Omagh bombing has disappeared from his home in the Border area and is thought to have fled the country, according to Garda sources.
The man's disappearance occurs as gardai are becoming increasingly confident of bringing substantive charges in relation to the bombing last August 15th in which 29 people were killed and 300 seriously injured. The man is a former senior Provisional IRA figure who defected in protest at the calling of a second ceasefire and set up his own terrorist group. It was responsible for more than a dozen bomb attacks in the North before Omagh.
Gardai were expecting to question the man as a result of information established about the workings of the republican group which calls itself the "Real IRA".
Meanwhile, the team of more than 40 detectives assembled in Monaghan Garda station to investigate the bombing were last night still questioning three men from the Border area and a Dublin woman.
The woman, who has connections with the splinter political party Republican Sinn Fein, was arrested in south-west Dublin yesterday morning and taken to Monaghan station, where she is being questioned about possessing explosives.
The three others are a Dundalk man who was previously arrested in connection with explosives charges relating to the "Real IRA", another Dundalk man with known links to the "Real IRA" and a man who lives just south of the Border in the Faughan area of Co Louth.
Gardai now believe they have an evidential basis on which to bring major charges in relation to the bombing.
One of the key pieces of evidence uncovered by detectives concerns the use of two mobile telephones discovered during a search of a house near the Border in December. One of these telephones was used in Omagh within a 30-minute period before and after the bombing.
Gardai have also established the identity of the men who stole the Vauxhall Cavalier car used to carry the Omagh bomb. It was stolen in Carrickmacross two days beforehand and detectives are understood to have both statement and eyewitness evidence in relation to the theft of the car.