The Saville Inquiry heard from what it believed would be the last of over 900 witnesses in 2004.
The inquiry then moved into its final stages. In his closing speech, the Counsel to the Inquiry Christopher Clarke QC said it was still unclear which soldiers shot the 27 civilians on the day, but he hoped it had held to account those "whose actions or inactions contributed to what happened".
When the inquiry ended in November it was expected its findings would be released in the spring of 2005.
But in December it was announced that the inquiry would reconvene to hear from a man known as Witness X.
Much of the evidence surrounded the role of the IRA, and whether or not they fired shots on Bloody Sunday.
One of those who came forward was a former Royal Navy sailor, who told the inquiry he was a quartermaster in the Official IRA in 1972.
Reg Tester, who is originally from Nottinghamshire, said he was given orders to keep all Official IRA guns out of the Bogside in case the army tried to move in during the march.
But Mr Tester said he lost his cool when he heard that people had been killed and tried to fire a rifle at soldiers on Rossville Street.
"I had taken a new weapon that I was unfamiliar with rather than an old one because the it had a higher rate of fire," he said.
"However, the gun jammed and because I was unfamiliar with such a new weapon, I was unable to unjam it, so I returned to the car."
The inquiry also heard from a former member of the Provisional IRA, who said he confronted an Official IRA man who had just fired a shot.
The witness, known as Provisional IRA Man 1, said he was angry because he believed that there had been an agreement there would be no shooting at the Army on that day.
He said the Official IRA man argued that he only fired after the Army had shot two people, but he said he then agreed not to fire any more shots.
Another member of the republican movement said he saw a man with a rifle and heard a shot before he heard shots fired by the Army on Bloody Sunday.
The witness, known as RM1, said he remembered feeling "very angry" because of the risk to the crowd.
He said he was watching a number of young men stoning a small barricade in the area of Little James Street when he heard a shot which seemed to have come from a building behind him.
The republican said as he ran up the stairs in the building he was thinking, "who is mad enough to fire a shot with all this crowd about?"
He said he grabbed a gun from one of two men, threw the weapon down the stairs and pushed the man after it.
The inquiry also heard from Derry businessman Brendan Duddy, who said he got assurances from both wings of the IRA that they would not have weapons in the vicinity of the civil rights march.
Mr Duddy also said that he passed on this information to the local police commander Frank Lagan, who subsequently told him that the Army's intention was to take out a few "soft targets" in an attempt to draw the IRA into a gun battle.
"I was appalled. I could not accept that a human being would kill another human being indiscriminately," said Mr Duddy.
Closing the Inquiry
In a emotive submission, Lord Gifford QC put it to the Inquiry that Jim Wray was murdered by a death squad of four soldiers, and the particular circumstances of his death were an "atrocity".
He urged Lord Saville to conclude that Jim Wray was shot in the back as he ran across Glenfada Park and then "mercilessly shot" a second time at very close range as he lay on the ground.
The lawyer said each of the four soldiers in the group had offered a pretext for opening fire which had been "contradictory and manifestly false".
He said the second shot was deliberately fired to "get a kill" rather than through any sense of being in danger
"That shot was one of the defining moments of that day," he said.
In November 2004 it was estimated that the Saville Report would be published in spring 2005.