Two senior Brazilian diplomats flew to Britain on Monday to join the investigation into the shooting to death last month by British police of a Brazilian man they had mistaken for a would-be suicide bomber.The killing of Jean Charles de Menezes (27), in a London underground train as police hunted for men who a day earlier had left bombs that failed to explode on three trains and a bus, has prompted calls for London Police Chief Ian Blair to resign.‘‘We are here to see how the investigation works,’’ Marcio Pereira Pinto Garcia of the Ministry of Justice told reporters as he and Wagner Goncalves of the Federal Prosecutor’s Office arrived at London’s Heathrow airport.The pair will meet Metropolitan Police Deputy Assistant Commissioner John Yates later on Monday, and on Wednesday, quiz investigators from the Independent Police Complaints Commission (IPCC), which probes all fatal police shootings.The IPCC complained last week that police had initially resisted the investigation.The failed attack came exactly two weeks after four suicide bombers killed 52 commuters on the London transport system.Blair, who initially praised the actions of his officers, has rejected the resignation calls and revealed at the weekend he did not know they had killed an innocent man until 24 hours after the shooting on July 22.Leaked documents from the IPCC investigation last week exposed blunders and cast doubts on initial accounts from police and witnesses that de Menezes had been behaving suspiciously and had tried to flee. Relatives of de Menezes have called on Blair to quit because of police mistakes and information they say was misleading.His namesake, Prime Minister Tony Blair, holidaying in Barbados with his family, has endorsed his police chief.Family members and supporters will stage a demonstration outside the Prime minister’s residence at Downing Street later on Monday, calling for a public inquiry into the shooting.Sunday newspapers said undercover officers who followed de Menezes after he came out of an apartment block as part of the investigation did not believe he posed an immediate threat. They were therefore shocked when armed police arrived at the train at Stockwell station in South London and shot him, the reports said, citing senior police sources. Meanwhile, British Home Secretary Charles Clarke said he was implementing a crackdown on extremists who incite hatred this week, as part of a raft of measures drawn up in the wake of the London bombings. Clarke also dismissed criticism of a plan by the government to deport security suspects to countries with poor human rights records, such as Jordan. —Reuters