Before the Omagh bombing on August 15th 1998, the Garda had infiltrated the so-called "Real IRA" with up to three agents who produced information that led to the interception of a number of planned bomb attacks.
By August 1998 the Garda and probably the RUC knew the identities of the principals in the "Real IRA" who had charge of the Omagh atrocity. There was intensive surveillance on the republican group that was trying to wreck the Belfast Agreement through bomb attacks.
The key sources were figures who were carrying out logistics tasks for the republican group.
The Irish Times understands that a Garda surveillance unit was aware of a premises in Co Meath which was being used by the "Real IRA" before the Omagh bombing. Two weeks before the Omagh bombing a vehicle was traced moving from this premises to the Border near Cullaville in south Armagh.
It was subsequently learned that this vehicle almost certainly carried the explosive mix which was used in Omagh. The vehicle escaped the Garda surveillance operation.
Within a few weeks of the investigation beginning into the Omagh bombing, gardai had information about the explosives being mixed in Kilcock. There was a description of a cement mixer used to mix fertilizer and diesel. The information included a description of foam-like residue being skimmed off the top.
The explosives were delivered to the key figure involved in preparing the Omagh bomb. He is a man in his 30s who lives near the Border north of Dundalk. His bomb-making skills were learned as a Provisional IRA member. He had made many landmines and car bombs while with the Provisional IRA. He oversaw the construction of the bomb and its placement in the boot of the stolen Vauxhall Cavalier that was driven to Omagh on the morning of the bombing.
Enough explosives were mixed in Kilcock to make two bombs. A test bomb was taken to the Cooley Mountains and detonated on August 6th.
The bomber set up poles with paper markers to determine the explosive force. The explosive mixture had a high level of incendiary mix, mainly diesel, causing widespread scorching of vegetation on the hillside. This mixture resulted in extensive burns to all 29 victims and most of the injured.
Before the test explosion the "Real IRA" leadership had decided to target Omagh - to display its ability to spread its bombing campaign across Northern Ireland.
The bombing was part of a series of attacks on the commercial centres of provincial Northern towns, started the September before when a 400 lb bomb in a van exploded near Markethill RUC station in Co Armagh. The dissidents were intent on stepping up their campaign to destabilise the Northern Ireland Assembly which was to meet again in mid-September.
From the first attack in Markethill to the Omagh atrocity, the republican terrorists caused nine explosions, including two test detonations and two attacks on the railway line; four mortar attacks on security bases; and abandoned six bomb runs, one of which was a 1,200 lbs bomb which was to be detonated in Portadown on the eve of the Twelfth of July.
Significantly, the Garda had intercepted at least six bomb attacks, seizing more than 7,000 lbs of explosive, stolen cars and making several arrests. It was clear from this run of successes from January to May 1998 that the Garda had very good inside information allowing them to intercept bomb attacks.
From May onwards the bombers began changing their modus operandi to identify and isolate the Garda intelligence source. They were able to carry out three bombings from June - at Drumintee, Newtownhamilton and Banbridge - without being intercepted. Garda sources say the group isolated its operations into smaller units and moved final preparations for bomb attacks into south Armagh, and out of the Garda's jurisdiction.
The Omagh bomb and the test device were almost certainly constructed in south Armagh. While the senior RUC officer in charge of the RUC's investigation was correct in stating at the Omagh inquest on October 1st that the perpetrators are mainly from Co Louth, the bomb was made and detonated in the RUC's jurisdiction.
Within months of the atrocity the Garda and RUC knew the identities of the 15 people involved in the bombing. About four or five of these people made the explosives and brought them to Cullaville in south Armagh. Two men stole the car from Carrickmacross for use in the bombing. Another four or five people made the bombs, carried out the test explosion and put the bomb in the car boot. This was overseen by a man in his 30s who lives near the Border in Co Louth.
This man then handed over to another man from Dundalk who delivered the bomb and made the warning telephone call from a public phone in Forkhill.
Two men, one from near the Border in Co Louth and another man in his 20s from Co Armagh but living in Co Louth drove the car. Ahead of them were two other men, both from near the Border in Co Louth, looking for possible checkpoints. The unit was in touch by mobile telephone with the man with responsibility for the bomb run.
The Omagh bombing and the campaign that started the in Markethill was directed by a man living in Co Louth who is still head of the terrorist group. After a ceasefire for over a year after Omagh, the group restarted its campaign. So far this year it has carried out 18 attacks on security bases in Northern Ireland; the railway line; and on targets in London.