At the time the raid was the biggest in British history
By Vincent Kearney
BBC NI home affairs correspondent
It was a stunningly audacious robbery, both in its scale and timing.
The political process in Northern Ireland was in crisis following the collapse of the Assembly because of allegations that the IRA had been running a spy ring at Stormont.
Then, four days before Christmas 2004, a highly organised gang stole £26.5m from the Northern Bank.
They did not dig a tunnel or use explosives, they simply took two families hostage in Belfast and County Down and made two bank employees bring the money to them.
At the time it was the biggest robbery in British criminal history, and one of the biggest anywhere in the world.
The robbers were highly organised and had detailed information about security procedures at the bank.
The judge found Chris Ward not guilty of all the charges
In total, the police estimated that up to 30 people may have been involved and they had no doubt who was to blame.
Speaking two weeks after the robbery, Chief Constable Sir Hugh Orde told a packed press conference: "On the basis of the investigative work we have done to date, the evidence we have collected, the information we have collected, the exhibits we have collected and bringing that all together and working through it, it is my opinion that the Provisional IRA were responsible for this crime."
The security assessment that the IRA had robbed a bank at a time when the British and Irish governments were locked in talks with Sinn Féin and other parties in a desperate bid to put together another political deal caused shockwaves.
Bertie Ahern, the Irish prime minister at the time, could not conceal his anger.
"It is of concern to me that an operation of this magnitude was obviously being planned at a stage when I was in negotiations with those who would know the leadership of the provisional movement and that raises questions, and questions that concern me," he said.
As the Northern Bank printed newly designed notes to render much of the money stolen useless, and politicians struggled to repair the damage caused, the police believed they were close to catching those responsible.
The gang that robbed the bank had such detailed knowledge about its security procedures that detectives believed they had an inside man, and that Chris Ward, a bank supervisor, was that man.
Mr Ward's family was one of those taken hostage by the gang. But rather than being a victim, the police believed the 26-year-old had been a willing accomplice and had been part of the conspiracy.
Police surveillance teams watched his home and even followed him on holiday to Spain, and almost a year after the robbery he was arrested and charged.
During his four week trial there was no mention of the IRA, no details of what happened to the money, and ultimately no evidence that Chris Ward had been part of the gang.
The prosecution case was based on circumstantial evidence.
It was claimed that Chris Ward had made a last minute change to the rota for the keyholders who had access to the bullion room where the money was stored in the bank to ensure that he was on duty, in order to facilitate the robbery.
But the trial judge Mr Justice McLaughlin said there was no evidence to support that claim, and that the fact that Mr Ward was on duty on the night of the robbery was the result of "coincidence and circumstance".
The prosecution also claimed that Chris Ward's family had been well treated by their captors - while the other bank employee and his wife were subjected to a terrifying ordeal.
But after Mr Ward's father broke down in tears while recalling the night he was taken hostage, the prosecution decided not to call any other member of the family to give evidence.
It was also argued that the fact that the robbers knew so much about security procedures at the bank demonstrated that an inside man had helped.
But they could not prove that Chris Ward or anyone else had provided that help.
The trial had been scheduled to last eight weeks but on Thursday the prosecution said that no further evidence would be given.
Mr Justice McLaughlin said the decision of the prosecution was "fully justified and proper".
"Given the decision to present no further evidence, I could not arrive at any other verdict and I conclude that Chris Ward is not guilty of the three counts in front of me," he said.
Almost four years on, it now seems unlikely that anyone will be convicted for the largest robbery ever in Ireland, a robbery that shook the political process to the core.
Republicans have always denied involvement, but there is little doubt that it was an IRA operation.
Why they did it remains a mystery: a last spectacular operation to show their supporters that they were leaving the stage from a position of strength?; a pension fund for members?; or simply an organisation that could not pass up an opportunity, no matter what the political consequences?
None of those questions were addressed during the trial, and it is unlikely the real story will ever be known.