By John Ware
BBC Panorama reporter
More than 10 years after the blast no-one has been convicted
The Omagh bombing was carried out by dissident republicans who had split from the main IRA body, known as the Provisionals or Provos, in protest at their decision to end the "armed struggle" against the British presence in Northern Ireland.
Provo leaders roundly condemned the actions of their former comrades in arms.
But what have the Provos actually done to help bring the perpetrators to justice?
The answer seems to be nothing.
According to intelligence reports, Provos, then on ceasefire, saw the maroon Vauxhall bomb car being guarded by two dissidents hours after it had been stolen.
They were challenged because they were suspected of having stolen the car for a bombing.
This sighting was in the hamlet of Culloville on the South Armagh/County Monaghan border.
The two individuals were identified by name and were seen moving the car to a destination, apparently unknown.
In August 2002, on the fourth anniversary of the bombing, the head of the PSNI Inquiry, Detective Superintendent Norman Baxter, pleaded for the IRA's political leaders in Sinn Fein to encourage their comrades to examine their consciences and go to the police.
This drew a defensive response from Sinn Fein's Mitchell McLoughlin who said: "Sinn Fein does not run any campaign dissuading people from giving information."
True, Mr McLaughlin had roundly condemned the bombing as had Martin McGuiness, Sinn Fein's chief negotiator, both of whom went to Omagh as soon as they heard about the atrocity.
Sinn Fein leader Gerry Adams also called it an "appalling act".
Sinn Fein leader Gerry Adams condemned the bombing
But Det Supt Baxter was right to say that none of them had ever actively encouraged their followers to go to the police on either side of the border.
To this day, ex-Provos who might have evidence that would be helpful to a prosecution have yet to come forward with witness statements, either to the police in the Irish Republic, the Garda Siochana, or the Police Service of Northern Ireland (PSNI), even though the bombing happened 10 years ago and Provo leaders now run the Northern Ireland Executive along with Unionists.
Eighteen of the 22 Omagh suspects live in the Irish Republic and although republicans were mistrustful of the Garda Siochana, republican ideological objection to dealing with them was not as deep as it was for the then Royal Ulster Constabulary north of the border.
For all republicans - dissident or otherwise - there was simply too much historical and political baggage attached to the RUC.
Can the same really be said a decade on given that policing has been radically transformed in Northern Ireland - and not just symbolically through the name change to the PSNI?
As members of the Policing Board, former IRA members now get to appoint chief constables.
Network of supporters
Det Supt Baxter also said the Omagh bombers would "have relied on a network of supporters to provide transport, acquire equipment, provide safe houses and wash clothes to destroy evidence".
This network, until about a year before Omagh, would have been part of the provisional IRA's own network and its members well known to members of Sinn Fein.
There seems little doubt that some Provisionals knew exactly who the Omagh bombers were.
Images of the suspect car were issued almost immediately
I am told that the day after the bombing the Provisional IRA Army Council met and passed the death sentence on their erstwhile IRA colleague Mickey McKevitt, leader of the dissidents, and on his lieutenant Liam Campbell who had organised the bombing.
Both were to be shot.
At the time Mr McGuiness, now First Minister of the Northern Ireland Executive, Mr Adams, President of Sinn Fein and, reportedly, Pat Doherty MP for West Tyrone, were serving on the Council.
The technical offence was not the murder of 29 people and two unborn babies, but using Provisional IRA munitions and logistics without authority.
For example, the Coupatan timer used in the Omagh bombing was part of a batch of 480 bought by the Provisionals from France in January 1997, 10 months before the IRA conference at Falcarragh, County Donegal when the Provos agreed to abandon violence.
The death sentence however was soon lifted.
Sinewy arguments broke out about whether it was right for republicans to kill fellow republicans who had not been informers.
'Read the riot act'
Instead, on 1 September 1998 - 17 days after the bombing - key members of the bomb team were visited and read the riot act by a representative of the Army Council on the orders of one of its members Thomas "Slab" Murphy, a millionaire pig farmer, oil smuggler and property owner whose farm straddles the border.
Omagh was the single biggest loss of life in the Troubles
The visits were organised by the IRA's Northern Command "Ops" officer Sean "Spike" Murray from Belfast.
Intelligence sources reported that those whose homes were visited were alarmed that the Provos knew precisely who they were.
By contrast there is no record of the detectives being briefed by the intelligence services as to who some of the suspects were for another eight days.
Det Supt Baxter was surely right when he said the Omagh bombers would have relied on a network of supporters.
Such witnesses almost certainly exist today and are quite likely to be members of Sinn Fein.
And yet for all Sinn Fein's condemnation, still no-one who saw or heard something that might just clinch a case worth prosecuting has made a witness statement to the PSNI.
For some of the relatives affected by the bomb, one incident illustrates how Sinn Fein has sought to navigate a credible course between verbal condemnation of Omagh whilst also keeping their heads below the parapet.
Members of the Omagh Support and Self Help Group wanted the words "murdered by a dissident republican terrorist car bomb" inscribed on a plaque in the memorial garden being built close to the scene of the atrocity.
Wording on the memorial has been contentious
The words "Murdered…republican terrorist…car bomb" are part of the Provo's bloody legacy from their 30-year campaign of terror.
But the town's Sinn Fein dominated district council could not commit to the words.
The council insisted they did not have a "pre-determined view" and were simply trying to get consensus amongst the relatives, victims and others who had expressed a "wide range of views".
After months of wrangling with the relatives, the council put the matter in the hands of "independent facilitators".
They recommended the words remain unchanged.
On the 10th anniversary of the bombing last month, the council's Sinn Fein leader cut the ribbon opening the memorial garden.
The Omagh Support and Self Help Group stayed at home.
Panorama: Omagh - What the Police Were Never Told will be broadcast on BBC One at 8.30pm on Monday 15 September.