The inquest into the killing of Jean Charles de Menezes by police hunting a suicide bomber has opened.
Brazilian electrician Mr de Menezes, 27, was shot at Stockwell Tube station, south London, the day after the failed 21 July 2005 London suicide attacks.
A jury will hear from two officers who fired the fatal shots - the first time their accounts will have been heard.
In his opening statement, coroner Sir Michael Wright warned jurors to concentrate on the evidence alone.
The jury will consider whether or not Mr de Menezes was unlawfully killed.
Former High Court judge Sir Michael, assistant deputy coroner for Inner South London, swore in the jury.
"It is for you, the jury, to determine the facts of this fatality and that task will be yours and yours alone," he said.
He added: "It must be stated at the outset of this inquest with the greatest possible emphasis that in truth Mr de Menezes was in no way associated with bombs, explosions or any form of terrorism."
Sir Michael told the jury rules prevented them from reaching verdicts which appeared to "determine any question of criminal liability on the part of a named person, or any question of civil liability at all".
Three of Mr de Menezes' cousins arrived at the inquest, set to last three months, flanked by members of the Justice 4 Jean campaign.
Alex and Alessandro Pereira and Patricia da Silva Armani made no comment as they entered the hearing.
They and other relatives have campaigned for police officers involved in the shooting to be prosecuted.
Mr de Menezes was shot dead on 22 July 2005 by specially trained Metropolitan Police firearms officers.
Teams of undercover officers had trailed Mr de Menezes across south London after he left flats being watched for one of the 21/7 bombing suspects.
Sir Michael outlined the role of police units involved in the operation, including the SO12 surveillance and CO19 firearms teams.
The jury will hear from some 75 witnesses including Tube passengers and 48 serving police officers who have been granted anonymity, although jurors will be able to see them.
Sir Michael said: "The officers themselves are genuinely fearful that they or their family might become subject to unwanted attention or reprisals if their identities became known to criminal or terrorist groups against which they are working."
Menezes inquest: how did we get here?
He said at the time of the shooting the police intelligence assessment of the level of threat posed to the UK by international terrorism "was raised to the very highest level - it is usually called critical".
He added: "You may feel able to conclude that the pressure on the police officers charged with the responsibility for investigating and tracking the persons responsible for this series of attempted bombings was substantially increased by the clear indication and fear that what had occurred might be the first and second of a series of similar attacks."
In 2007, an Old Bailey jury found the Metropolitan Police guilty of breaching health and safety laws, after hearing about the events leading up to Mr de Menezes being shot seven times at close range on a Tube carriage.
As the hearing opened, an internal memo from Met Police Commissioner Sir Ian Blair to his staff was leaked.
In it, he says the inquest is the right place for the force to "account for" its actions, adding "our approach will be one of humility".
Among those who will be speaking for the first time at the inquest will be policemen codenamed C2 and C12, the two specialist firearms officers who shot Mr de Menezes.
Some of the other officers giving evidence appeared at the Old Bailey trial, including surveillance officers accused of failing to establish whether or not the man they were following matched the description of suicide bomber Hussain Osman.
Speaking in his hometown of Gonzaga, Mr de Menezes' brother Giovani da Silva told the BBC that the three-year wait for the inquest had been "a real torture".
"We want to be finished with this anguish so we can have some peace," he said.
"Since they killed Jean Charles our mother has been depressed and very sick. All of this causes her too much sickness which is why we just want this to end soon so we can have some relief."
Mr da Silva said the police officers involved should not be allowed anonymity.
"Their images should be shown to the public so everyone knows who these inept policemen are," he said.
The Menezes' spokesperson on what they hope the inquiry will achieve
The inquest is being held at the John Major conference room at the Oval Cricket Ground because of the scale of the proceedings and level of public interest.
Mr de Menezes' mother, Maria, and brother Giovani, are expected to fly from Brazil to attend the later stages of the inquest, including evidence given by the two shooters.
There have been five inquiries relating to the death and its aftermath, including the criminal trial.
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