The family of Jean Charles de Menezes has made a new demand to see the report on his death after details from it were apparently leaked to a Sunday paper.
Mr Menezes was killed after being mistaken for a suicide bomber
The Brazilian was shot dead by police in London in July after being mistaken for a suspected suicide bomber.
The News of the World claims the report - by the Independent Police Complaints Commission - says some police evidence about his death was falsely rewritten.
The Metropolitan Police said it would not be appropriate to comment.
'Last to know'
Mr Menezes, a 27-year-old electrician, was shot dead at Stockwell Tube station the day after the failed 21 July bombings.
A report by the IPCC, which has carried out an investigation into his death, was passed to the Crown Prosecution Service on 19 January.
Copies have also been sent to Scotland Yard, the Metropolitan Police Authority and Inner South London coroner John Sampson.
The IPCC has said the Menezes family will be allowed to see it when "legal considerations" allow.
But, in a statement issued on 19 January, the family said: "We think it is unacceptable that yet again the victims in this tragedy are the last to know."
The report will not be made public until any trial or inquest arising from the case has been completed.
A separate IPCC investigation is being held into Metropolitan Police Commissioner Sir Ian Blair's handling of the affair.