London ? Prime Minister Tony Blair warned on Saturday that an “evil ideology” of Islamic extremism was bent on spreading terror through the West, and authorities on three continents widened investigations into the London terrorist bombings. The number of people confirmed dead rose to 55.

Police in the northern city of Leeds searched an Islamic shop, the home of an Egyptian biochemist and a third address for more evidence after investigators reportedly found traces of explosives in the Egyptian’s bathtub.

Also, police moved the twisted wreckage of the double-decker bus where one of the bombers and 13 other people died. The bus became a symbol of the capital’s worst attack since World War II. Londoners and tourists stopped to watch as police used a flatbed truck to haul away the tangled wreckage for forensic testing.

Police also released an image captured by surveillance cameras showing all four bombers with backpacks entering the train station in Luton, north of London, on the morning of the July 7 attacks. Investigators say the four took a train from Luton to London’s King’s Cross station, where they split up to carry out the bombings.

Police on Saturday moved the twisted wreckage of the double-decker bus where one of the bombers and 13 other people died. The bus became a symbol of the capital's worst attack since World War II.

The Sunday Times reported that one of the suspected attackers, 30-year-old Mohammad Sidique Khan, was scrutinized last year by the MI5, Britain’s domestic secret service, but was not regarded as a threat to national security or put under surveillance. The scrutiny came during an inquiry into an alleged plot to explode a truck bomb outside a target in London, the paper said. The inquiry looked at hundreds of potential suspects, it said.

The Metropolitan Police declined to comment on the report, and spokesmen at the Home Office, which deals with queries about national security, were not immediately available Saturday night.

The hunt for clues pointing to those who recruited, financed and supplied the four suicide bombers who blew up three underground trains and the bus focused on the men’s ties to Pakistan. Authorities in Islamabad said they questioned students, teachers and administrators at one of two religious schools believed visited by one of the suspects.

Asad Farooq, a spokesman for the school, told The Associated Press that intelligence agents had been there Saturday but denied that the suspect, Shahzad Tanweer, had ever been at the school. British investigators say Tanweer, 22, carried out the bombing of the London Underground’s Aldgate station.

ABC television reported Saturday that the FBI was looking into possible ties between unidentified people in New Jersey and a Jamaican-born Briton, whom British authorities formally identified for the first time Saturday as Germaine Lindsay, 19.

In this CCTV image made available Saturday by the Metropolitan Police, the four London bombers are seen arriving at Luton railway station July 7. The image shows, from left, Hasib Hussain, Germaine Lindsay, dark cap, Mohammed Sidique Khan, light cap, and Shahzad Tanweer.

Police said he died in the worst of the suicide attacks – a subway bomb that killed at least 26 people between the King’s Cross and Russell Square stations.

FBI spokesman Ed Cogswell said Saturday the agency had no comment on any pending investigations.

Authorities raised the death toll from 54 to 55 after an injured victim died overnight at a hospital. About 700 people were injured in the morning rush-hour attacks, and police said more than 40 people remained hospitalized, at least six of them in critical condition.

In a speech in central London on Saturday, Blair said authorities were facing an “evil ideology” in their struggle against Islamic terrorism.

“The greatest danger is that we fail to face up to the nature of the threat that we’re dealing with,” he said. “And what we are confronting here is an evil ideology. … It is a battle of ideas, of hearts and of minds, both within Islam and outside it.”