The Omagh bombing is not just the most serious atrocity of the Troubles, it is also the largest mass murder in British or Irish legal history.
Tony Blair, the Prime Minister of the day, called it an "appalling act of savagery and evil" and pledged to leave no stone unturned to find the perpetrators. Yet the more we hear about his Government's role the more awkward the questions become.
The role of Garda intelligence, one of whose agents allegedly supplied the bomb car, is also questionable. Today Norman Baxter, who investigated the bombing, has raised important issues about what the British Government knew in the hours after the bombing when investigative opportunities were lost.
Was someone in authority weighing up the overall interests of the peace process and securing the IRA ceasefire against the need to solve the most significant crime ever to have occurred in Britain or Ireland?
Could mass arrests or military incursions in south Armagh and north Louth, where the bombing was planned, have broken the influence of the pro-peace process republican leadership or provoked a deeper IRA split?
Instead the shame of the unsolved bombing broke the back of RIRA and forced it to a ceasefire. But the bombing went unsolved and there was no justice for the bereaved.
These questions are so painful that no civilised society can leave them unanswered.
The most appropriate vehicle to put this issue to rest may be a panel of experts who can examine all intelligence and political decision-making in the wake of the atrocity and have the authority to produce a report.