Pleading anew for help from the public, British police on Saturday released a security camera photo of four suspected bombers entering a train station together on the morning they allegedly carried out the rush-hour attacks that killed at least 55 people, including themselves.

Dressed in light jackets, blue jeans, T-shirts and running shoes, with two of them wearing baseball caps, the four looked like backpackers heading off for a vacation. They are shown entering Luton station north of London at 7:20 a.m. on July 7, toting bags that investigators say each contained 10 pounds of explosives.

The authorities confirmed the names of the last two men who had not been officially identified and urged witnesses to come forward. "We still need to find out more about these four men and their movements, both on the morning of the bombings, and in the days and weeks beforehand," Peter Clarke, head of the anti-terrorist branch of Scotland Yard, Britain's national police force, said in a statement.

More details emerged about the suspected fourth bomber, whom police formally identified as Germaine Lindsay, 19, a Jamaican-born British national who changed his name to Abdullah Shaheed Jamal when he converted to Islam. Police said his body has been identified at the site of the deadliest attack, the Piccadilly line subway train between King's Cross and Russell Square, which claimed 26 lives.

Lindsay grew up in a single-parent household in southern England, went to local schools, and converted to Islam at the behest of his mother, who also became a Muslim, according to a report in the Guardian newspaper. She remarried and moved to Cleveland, Ohio, about three years ago, and has since relocated to an unknown address.

Lindsay met and moved in with an English woman, Samantha Lewthwaite, and lived in public housing in the city of Huddersfield, about 15 miles southwest of Leeds, where the other suspects lived. He worked as a carpet layer and sold cell phone covers on weekends at a local market.

Lewthwaite gave birth to a son 15 months ago, and a few months later the couple moved to Aylesbury, about an hour's drive northwest of London, where they rented a small red-brick house that police have been searching for three days. Lewthwaite, 22, who is pregnant with the couple's second child, told the Sun newspaper she refused to believe that Lindsay was one of the bombers. "I'm not going to accept it until they have his DNA," she said.

The other suspect who was formally identified by police on Saturday was Mohammed Sidique Khan, 30, a teaching assistant at a Leeds public school who was alleged to have bombed a subway train at the Edgware Road station. Khan's family issued a statement expressing their "deepest sympathy" to the victims of the bombings and their relatives and calling on people to "expose the terror networks which target and groom our sons to carry out such evils."

"We are devastated that our son may have been brainwashed into carrying out such an atrocity, since we know him as a kind and caring member of our family," the statement read.

In Cairo, Egypt's interior minister told a newspaper that an Egyptian biochemist held for questioning over the bombings has no links to the al Qaeda network. Habib Adli told the daily Al-Jumhuriyah that media speculation about Magdy Mahmoud Nashar was groundless.

Egyptian authorities arrested Nashar at the request of British investigators because he reportedly served as a go-between in renting a townhouse in Leeds that was allegedly used in the bomb plot. He has denied any role in the attacks. Police in Leeds sealed off and searched another house Saturday.

In a speech to members of his ruling Labor Party in London, Prime Minister Tony Blair said Saturday that the world was facing an "evil ideology" in Islamic terrorism, and insisted that the bombers were motivated by deep hatred and not policies such as Britain's participation in the U.S.-led war in Iraq.

But Clare Short, who resigned as a cabinet minister over the Iraq war, said she "had no doubt" the attacks were linked to Iraq and to British policy in the Israeli-Palestinian conflict. "We are implicit in the slaughter of large numbers of civilians in Iraq and supporting a Middle East policy that for the Palestinians creates this sense of double standards, that feeds anger," she told GMTV in an interview to be broadcast Sunday.

British media reports said the government would propose security measures early next week that would establish "acts preparatory to terrorism" as a crime in order to make it easier for authorities to intervene during the planning of an attack. The measures would also outlaw training in terrorist techniques either in Britain or abroad and ban "indirect incitement" that condones or encourages others to participate in terrorist acts.