Allesandro Pereira, 25, a cousin of Mr de Menezes, called on Sir Ian to resign and for the officers involved in the shooting to be prosecuted.
Delivering an emotional statement at a news conference in London, he said: "For three weeks we've listened to lie after lie about Jean and how he was killed."
Mr Pereira also asked whether evidence had been lost in the six days before the IPCC became involved. Yesterday the IPCC said it had to "work hard" to recover lost ground after the Met had "initially resisted" the external investigation.
Sir Ian insisted that there had been no cover-up and any delay was because of the huge counter-terrorism operation under way at the time.
And this - Brazil are taking this extremely seriously - as I hoped they would:
A statement today from Brazil's foreign ministry said the disclosures leaked to the media this week over the killing of the innocent Brazilian had "outraged" the government.
Judicial officials will visit London on Monday to meet with the Independent Police Complaints Commission (IPCC), which is investigating Mr de Menezes' death, and the Metropolitan police. The Brazilian foreign ministry said it expected the officials to "obtain ample clarifications".