The Independent Police Complaints Commission (IPCC) on Tuesday promised “rigorous, detailed and far-ranging” investigation, whose findings would be ready by the end of the year.
But it warned that publication could be delayed if any legal proceedings are necessary.
Two Brazilian government officials, meanwhile, continued their own investigation into how police mistook Jean Charles de Menezes, a 27-year-old electrician, for a bomber.
Menezes was shot seven times in the head and once in the shoulder on July 22 after police tailed him onto an Underground train.
They shot him a day after four failed bomb attacks on London's transit system.
New revelations have suggested that police failed to properly identify Menezes, some of the officers tailing him didn't believe he posed an immediate threat, and armed police who shot Menezes fired at him even after he'd been restrained.
Leaked documents also contradicted initial statements that said Menezes had been dressed in a bulky coat despite the warm weather and had run from police.
Menezes was shot a day after
four failed bombs in London
And this week, a new row emerged over footage from the closed circuit television cameras in the Stockwell station where Menezes was killed.
Police reportedly told Tube employees that the tapes were useless, something the staff allegedly disputed.
Such tapes could provide key evidence of Menezes's behaviour inside the subway station and the actions of officers following him.
Metropolitan Police refused to comment on allegations that police might have tampered with the tapes, saying it was appropriate only for the agency leading the investigation, the IPCC, to make all public statements now.
With new allegations emerging daily, the IPCC said its goal was to stay focused on its investigation.