The sister of Guildford Four member Gerry Conlon has called for secret papers on his case to be made public after a small number were released to the BBC.
Mr Conlon and three others were jailed in what is widely regarded as one of the worst miscarriages of justice in British history.
Previously unseen files from an inquiry into the case indicate persistent attempts to try to “reconvict” the four, Mr Conlon’s lawyer has said.
His sister Ann McKernan said releasing the documents would reveal the truth.
Following a freedom of information request, the first six files from Sir John May’s five-year probe into the Guildford case were released to the BBC after an extraordinary process of censoring files that took nearly a year.
However, the vast majority of the files - more than 700 - have remained secret.
Mr Conlon, Paddy Armstrong, Paul Hill and Carole Richardson, who always protested their innocence, served 15 years before their convictions were quashed by the Court of Appeal in 1989.
All made signed confessions after being subjected to violence, threats to their family and intimidation.
They were charged with the Guildford bombings, but later retracted their statements. But all four were found guilty and received life sentences.
A unit of the Provisional IRA subsequently claimed responsibility. It was only after a campaign that received support from high-profile politicians and law lords that the four were finally released.
It was Gerry Conlon’s dying wish to see evidence gathered as part of an inquiry into the case made public. He believed it could help other justice campaigns, such as one he spearheaded on behalf of the Craigavon Two, which remains deeply controversial.
Mrs McKernan said the Conlons were “an ordinary Catholic family” growing up in the Falls Road in a working-class area. “My family weren’t republicans,” she said.
She said her brother always believed the files contained important information. “He knew that there was stuff in there that had to be released to the public,” she said.
Files released so far have shown some inquiry members blankly refused to believe Mr Conlon’s assertion that he was not in the IRA.
One February 1994 memo headed “Conlon’s Proof” quotes a document suggesting Mr Conlon admitted he was a member of the IRA until 1974.
It gives “three reasons” to believe the statement was true, all based on irrelevant “intelligence” reports which even London Special Branch police admitted “amount to very little”.
Lawyer Alastair Logan, who represented Mr Conlon in the years following his conviction, said the documents were not comprehensive, but showed a persistent attempt to try and ‘reconvict’ the Guildford Four was still going on after their acquittal.
He said a “whispering campaign” began, primarily motivated by police but also by others whose reputations were involved.
“It wasn’t just police. It was law officers and certain judges,” he said.
Richard O’Rawe, Mr Conlon’s biographer, said the British were determined to pin something on them: “They wanted to establish some kind of guilt - it was guilt by association.”
He said that during the early 1990s people tried to make out Mr Conlon was in the IRA, but he added that the Guildford Four “were just a bunch of hippies” without the discipline and reliability to be part of a “military machine”. Mr O’Rawe said his friend was left “burning up inside” because he never saw the files.
A British government spokesman said it did not comment on matters of national security.