Brazilian investigators will fly to London next week for talks with their British counterparts over the shooting of Jean Charles de Menezes by police.
Brazil wants the Independent Police Complaints Commission (IPCC) to clarify conflicting reports of how Mr Menezes died at Stockwell station on 22 July.
Investigation papers leaked to the media this week seemed to contradict the police version of events.
Despite pressure, Met Police chief Sir Ian Blair has said he will not resign.
The IPCC has said Scotland Yard "initially resisted" its attempts to launch an investigation into the shooting, reports BBC.
According to Guardian, Sir Ian Blair, the Met police commissioner, decided he did not want an independent inquiry, and wrote immediately to Sir John Gieve, the permanent secretary at the Home Office, citing issues of national security.
This was a unique situation, he argued, insisting the anti-terrorist operation must take priority, and that bringing in another set of investigators, from the Independent Police Complaints Commission, was not a viable option, given the highly sensitive intelligence involved.
This has led to accusations of a cover-up, with the lawyers for the family of the innocent victim Jean Charles de Menezes claiming the delay could have meant the loss of "vital evidence" and calling for Sir Ian's resignation.
The lawyers say Sir Ian created a false impression that Mr de Menezes had given the police cause to open fire, but leaked statements from the IPCC report show he did nothing to arouse suspicion.
One member of the victim's family has described the July 22 police shooting as "murder" and called for the officers who killed Jean Charles de Menezes to be "sent to jail for life."
The developments follow a TV news report citing leaked documents and photographs that contradict witness and police statements that the 27-year-old electrician was dressed and behaving suspiciously.
ITV News reported Tuesday that de Menezes was not carrying any bags when he entered the Stockwell Tube station where he was killed and was wearing a denim jacket, rather than a bulky coat as police had previously said.
De Menezes walked at a normal pace, did not vault any barriers and even stopped to pick up a newspaper, ITV reported.