Get the latest updates as we post them — right on your browser

. Last Updated: 07/27/2016

Terror Investigation Grows as London Mourns

LONDON -- Authorities are fearful of more terrorist attacks in Britain until the people behind Thursday's bombings on the capital's transport network are captured, Home Secretary Charles Clarke said Sunday as investigators trying to identify the attackers continued to pore over videotapes and photos.

"The fact is the terrorist threat is a real one as we saw so dramatically and awfully on Thursday," Clarke, the Cabinet minister responsible for law and order, told BBC television.

"Our fear is of course of more attacks, until we succeed in tracking down the gang which committed the atrocities on Thursday, and that's why the No. 1 priority ... has to be the catching of the perpetrators," he added.

The city's shock was evident Sunday as people gathered for memorial services across the capital to remember the more than 49 people killed and 700 injured. More than 20 people were still in critical condition in London hospitals.

Hundreds of fliers and photos appeared, pleading for information about loved ones not heard from for days, and scores of flower bouquets were placed outside King's Cross subway station.

With the country on heightened alert, police on Saturday night evacuated 20,000 people from the entertainment district in central Birmingham after intelligence suggested a security threat.

Crowds in the city center faced "a real and very credible threat," police Chief Constable Paul Scott said Sunday. He declined to describe the nature of the threat but said the danger had passed.

Police carried out one controlled explosion on a suspect bag on a bus, but concluded that it was not a threat. Scott said the suspect package was not related to the larger security threat.

Investigators, who on Saturday revised the timings of the subway blasts to near simultaneous instead of almost half an hour apart, are looking at claims by two al-Qaida-inspired groups that they carried out the bombings.

Former Metropolitan Police chief John Stevens said he believed the bombers were "almost certainly" British and that there were around 200 more people born and bred here willing to attack. "They are also willing to kill without mercy -- and to take a long time in their planning," Stevens wrote in an article in the News of the World newspaper Sunday. He said the police had thwarted eight attacks in the past five years.

Clarke said that investigators, who are also working with foreign intelligence agencies, were keeping an open mind about the origins of the attackers, but acknowledged that there were British citizens whom the government suspects of terrorist activity.

British media said investigators had asked their European counterparts, including Europol, to search for Mohamed al-Guerbouzi, a 44-year-old Moroccan who was given asylum in Britain.

Europol spokesman Rainer Wenning declined to comment on the reports.

However, al-Jazeera, the Arabic news organization, reported on its web site that it had interviewed al-Guerbouzi, quoting him as saying British authorities knew his address in London.

Mustafa Setmarian Nasar -- a Syrian suspected of being al-Qaida's operations chief in Europe and the alleged mastermind of last year's Madrid railway bombings -- has emerged as a suspect in the London attacks, according to unidentified investigators cited in The Sunday Times, The Sunday Telegraph and The Mail on Sunday. London's Metropolitan Police said they would not comment on the names of any suspects.

The confirmed death toll from Thursday's attacks was 49, but police said it inevitably would rise above 50 after teams of police, forensic scientists and investigators removed bodies still in London's vast Underground transport system.

It was not known how many bodies remained inside the Russell Square subway tunnel, but difficult conditions -- including temperatures of up to 60 degrees Celsius, asbestos and rats -- made recovery impossible.

"It is a very harrowing task," detective Jim Dickie said. "Most of the victims have suffered intensive trauma, and by that I mean there are body parts as well as torsos."

Forensic experts were relying on fingerprints, dental records and DNA analysis to identify the victims. None of the 49 dead has been formally identified.

After reviewing data from the Underground, police concluded that the blasts that tore through the subway system happened within a minute of each other, suggesting they were detonated by timers rather than suicide bombers. The bus bomb exploded nearly an hour later.

Initial investigations showed that the bombs contained high explosives, suggesting the material was not homemade. It was possible the explosives were industrial or military materials bought on the black market, police said, although investigators said it was too early to pinpoint the explosives' origins.