British Army veteran Dennis Hutchings, who had been on trial over a Troubles shooting, has died after contracting COVID-19.
The former soldier died in a Belfast hospital on Monday.
The trial had already been adjourned for three weeks after he caught COVID.
Defence barrister James Lewis QC had informed Belfast Crown Court of the COVID diagnosis as proceedings in the non-jury trial were due to begin on Monday.
He told judge Mr Justice O'Hara that Hutchings' condition had been confirmed by a PCR test on Saturday, saying: "I regret Mr Hutchings is not well with regard, as one would expect, with his other co-morbidities of renal failure and cardiac malfunction."
Hutchings, 80, had been suffering from kidney disease and the court had been sitting only three days a week to enable him to undergo dialysis treatment between hearings.
He was charged with the attempted murder of John Pat Cunningham in Co Tyrone in 1974, which he denied.
The former member of the Life Guards regiment, from Cawsand, Cornwall, also denied a count of attempted grievous bodily harm with intent.
Mr Cunningham, 27, was shot dead as he ran away from an Army patrol across a field near Benburb.
People who knew him said he had the mental age of a child and was known to have a deep fear of soldiers.
In a statement, the Cunningham family said they wished to acknowledge that this is a difficult time for the Hutchings family, adding they should be given time to grieve and will respond in greater detail in due course.
Democratic Unionist Party leader Sir Jeffrey Donaldson called the veteran's death "desperately sad news", but said that "serious questions" needed to be answered.
"Whilst understanding the desire of the Cunningham family for justice, we have consistently challenged those in legal authority who insisted that Dennis stand trial again," he said in a statement.
"He was an 80-year-old veteran, in ill-health on dialysis and there was a lack of compelling new evidence.
"There now stands serious questions around those who made the decision that Dennis should stand trial once more. He was honourable. He wanted to clear his name again but was dragged to a court and hounded until his death.
"This is a sad indictment on those who want to rewrite history but also demands serious questions of the Public Prosecution Service about how this trial was deemed to be in the public interest."
In a statement, Traditional Unionist Voice (TUV) leader Jim Allister said on Monday: "The needless dragging of an 80-year-old soldier, Dennis Hutchings, through the courts has had a very sad end with the passing of Mr Hutchings this evening.
"The strain on this man was cruel, with him requiring regular dialysis, while being brought to Belfast to face a trial of dubious provenance.
"My thoughts and prayers tonight are with his family and friends who may understandably feel that what he was put through contributed to his decline."
On Tuesday, Northern Ireland's Public Prosecution Service defended its decision to prosecute Hutchings, saying the decision to prosecute was taken after an "impartial and independent application of the Test for Prosecution".
Ulster Unionist Party leader Doug Beattie called for a "full and thorough" review into the decision-making of the Public Prosecution Service.
"I would like to convey my sincere condolences to Mr Hutchings' family and friends," Mr Beattie said on Monday.
"The decision by the Public Prosecution Service to proceed with a trial given his ill-health demands a full and thorough independent review.
"The questions must be asked, did this trial hasten Mr Hutchings' death and did it meet the evidential and public interest tests?"
Danny Kinahan, the Veterans Commissioner for Northern Ireland, said that the news was "incredibly sad".
On Twitter, he wrote: "I got to know Dennis over recent years. An elderly man, in poor health, he was determined to clear his name once and for all.
"Deepest condolences & sympathies to his wife and family at this difficult time."
DUP MP Carla Lockhart also described the news as "awful".
She tweeted: "Such sad news that he never got to live out his last days in peace. Awful. Spent last months of his life being hounded by a political show trial."
Sinn Fein MP Michelle Gildernew also reacted to the news on Monday night.
She tweeted: "I'm aware that there is a grieving family following the death of Dennis Hutchings," and added that the "family of John Pat Cunningham also continue to grieve tonight".
"Let's remember that grief knows no bounds," her tweet ended.
The Progressive Unionist Party said it extended its "profound sympathies" to the family of Mr Hutchings.
The party's armed forces spokesperson, Jim McCaw, said: "It is shameful that a veteran was hounded in his last days instead of being at home with his loved ones."
Raymond McCord, whose son was killed by loyalist paramilitaries in north Belfast in 1997, said he cannot understand politicians criticising the justice system, adding that what Dennis Hutchings faced was done in a "democratic fashion" through the courts.