Relatives of the Bloody Sunday victims and some traumatised eyewitnesses have been receiving professional counselling in the weeks leading up to the start of oral hearings by the new inquiry, as mixed and powerful emotions are stirred up by the prospect of reliving the terrible events.
There is a constant flow of people to the building in Shipquay Street where the Bloody Sunday Trust has set up a historical exhibition and visitor centre, providing rooms for consultations with the families' legal teams and for counselling sessions.
The availability of expert grief counselling was seen by the trust as essential as hundreds of civilian witnesses faced the ordeal of recalling their experiences in detail for the solicitors assembling witness statements in advance.
"There are people out there who badly need support. There was a woman sitting there in tears yesterday," said Mr John Kelly, spokesman for the relatives. "It's a matter of preparing the families for it. The wounds have been opened up again through people giving evidence to Eversheds [the tribunal's solicitors]."
The emotions aroused at this point are varied and often conflicting. There is a slight dawning of hope - not yet strong or universal - that the new inquiry may uncover important aspects of the truth and redress the deep wrong seen to have been inflicted by the late and much despised Lord Widgery.
But there is substantial and widespread fear that, yet again, they will be let down by British justice. Memories are still alive of the shock and disappointment caused when the Widgery Report, in a finely gauged play of words and against the mass of eyewitness evidence, justified the actions of the soldiers and left a general slur on those who had been in the Bogside that day.
While Widgery admitted that none of the dead or wounded had been proven to have been shot while handling a gun or bomb, he added: "Some are wholly acquitted of complicity in such action; but there is a strong suspicion that some others had been firing weapons or handling bombs . . . and that yet others had been closely supporting them."
That allegation outraged not only the families of the victims but the entire community, and since then the primary and overriding demand has been for an unqualified vindication of their innocence.
Mr Michael Bradley, now in his 50s, admits - like many others - to being obsessed with the events of Bloody Sunday, the inquiry and the vast mass of new material which is emerging. He was 20 when he was shot and badly wounded by a paratrooper at close range.
He admits that something "flipped" in his head that day when he was told that his friend, Jackie Duddy, had been shot dead. In total disbelief that live rounds could have been fired, he ran out from Rossville Flats towards the body on the ground and, realising the terrible reality, he began to shout, crazily, at the soldiers as they took aim at him.
He spent three months in hospital, missing the Widgery tribunal and having no opportunity to tell his story. Now his single-minded concern is to have his innocence vindicated, and he will give evidence to Lord Saville, even though he has lost faith in the inquiry. "I was all for him when he came. I was going to give him the benefit of the doubt," he says. "But, two years down the line, I think this is going to be another Widgery."
Others are also yielding to scepticism as they perceive that the British Ministry of Defence has succeeded in imposing limits on the tribunal. Yet they are keenly aware of the obvious contrast between this and the original hasty inquiry - the immense detail which is being assembled and Lord Saville's avowed commitment to total openness and impartiality.
While a new generation has grown up which had no direct experience of the devastating impact of the killings, the memory - and the sense of abiding injustice - has remained vivid among Derry's close-knit Catholic community. For the 25th anniversary commemoration in 1997 almost 40,000 people took to the streets.