LONDON – Commuters returned to work in London on Monday, the start of the first full week since bombers killed at least 49 people on a bus and subway trains. Many travelers said they would defy the attackers by using public transportation as normal, but some were too afraid and took taxis instead.

&#34I … will not let the attacks put me off,&#34 said computer consultant Paul Williams, 42, as he prepared to board an underground train in central London. &#34As far as I am concerned, it is just a normal day at work.&#34

But Ted Wright, chairman of the British Poultry Council, said he was taking a taxi to avoid the subway system. &#34In light of what has happened, I have decided to take a taxi. It will probably cost an extra six pounds ($10.70), but should hopefully put my wife”s mind at rest,&#34 he said.

Three bombs that exploded on subway cars and one that ripped apart a bus killed at least 49 people and injured 700 last Thursday.

Scotland Yard said Monday it had identified the first of the victims — Susan Levy, 53, of Hertfordshire, outside London. Forensics experts have warned that it could take days or weeks to put names to the bodies, many of which were mangled in the blasts.

Transit officials said the number of passengers using the system Monday morning was back to normal. However, a few sections of the underground rail system affected by the attacks remained closed, and the number of shoppers in central London has fallen by about 25 percent since the attacks, the British media reported.

Mayor Ken Livingstone took the subway to work Monday to send the message that Londoners should &#34carry on.&#34

&#34We are going to work. We carry on our lives,&#34 he said. &#34We don”t let a small group of terrorists change the way we live.&#34

For investigators, Monday was another pressure-packed day of sifting through subterranean debris, checking tips from the public and identifying the dead and missing.

Police said three men — all Britons — arriving at Heathrow airport were arrested early Sunday, but immediately dismissed speculation of their having a break in the investigation. The three were released late Sunday night.

British intelligence officials met over the weekend with their counterparts from the United States, Canada and about two dozen European countries to brief them on the attacks and the investigation, police said Monday.

Security officials in Poland said Monday they searched the home of a British citizen of Pakistani origin in the eastern Polish city of Lublin in connection with the bombings. Poland”s Internal Security Agency did not release the man”s name and he was not arrested.

A man with British and Moroccan nationality mentioned as a possible suspect told The Guardian newspaper in an interview published Monday that he had nothing to do with the blasts.

&#34Over 30 years I have lived in Britain, I have never been involved in violence or crime,&#34 said Mohamed Guerbouzi, who was convicted in absentia in Morocco in 2003 and sentenced to 20 years in prison in connection with the Casablanca terrorist bombings.

&#34I”m scared for my safety,&#34 Guerbouzi said.

Police said they were still working to recover the remaining bodies from one of the trains damaged in Thursday”s blasts.

More than 70 feet below the surface, teams of workers — clad in white suits and wearing face masks to protect them from the dust — dealt with sweltering heat and rats as they removed some of the bodies from the train wreckage in the tunnel between Russell Square and King”s Cross.

It was unknown how many more bodies remained below, but searchers said conditions were unlike any they had encountered before.

The Rev. Nicholas Wheeler of the Parish of Old St. Pancras, who has been at King”s Cross since Thursday, said Sunday that the toll on the rescue workers has been enormous.

&#34Obviously some are young people who have never seen horrors like this before, and they were emerging shell-shocked,&#34 he said.

On Sunday, Queen Elizabeth II led commemorations of the 60th anniversary of the end of World War II in Europe. Thursday”s attacks were not forgotten, and in speeches, officials noted a determination that Britain had suffered worse and would survive its latest tragedy.

A Royal Air Force Lancaster bomber older than many in the crowd released millions of red paper poppies, which fell gently on the crowd below.

Elsewhere, people mourned the missing and the dead, but top leaders of Britain”s Christians, Muslims and Jews urged conciliation, not revenge. They met &#34to proclaim our wish to resist any form of violence and to work for reconciliation and peace,&#34 Cardinal Cormac Murphy O”Connor said.

Yet there were some reports of violence toward mosques around Britain, including arson attacks on mosques in east London, Leeds, Telford and Birkenhead which resulted in minor damage. There were also reports of damage at two mosques in Bristol.

Chris Fox, president of the Association of Chief Police Officers, said it was likely there were other incidents that had not been reported.

&#34We encourage everyone to report this type of obnoxious and dangerous behavior, from whatever quarter, for full police investigation as we are determined that there will be a very robust enforcement response to it,&#34 he said.

Investigators remained silent on suspects in the bombings, but reports in London newspapers Sunday identified a possible suspect as 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.

London police refused to comment, but a U.S. official said that both nations were trying to locate Nasar.

&#34He has been a longtime and well-known bad guy terrorist, and involved in terrorist circles,&#34 Fran Townsend, President Bush”s homeland security adviser, said on the Fox television network.