LONDON — On their way to London to unleash terror and death, the suspected suicide bombers looked like students on their way to school or friends leaving on vacation.

A photograph police released yesterday showed them walking along a wet sidewalk, wearing jeans and loose jackets. One carries what looked like a grocery sack, as if bringing along a snack for the trip.

They also each carry a backpack. Police think each backpack contained 10 pounds of high explosives.

The close-circuit television photo was taken as the four walked into Luton train station at 7:21:54. They're a 35-minute train ride from the King's Cross station, where they'll split up on different subway lines and a double-decker bus. They're about 88 minutes from the first three of the four explosions July 7, which killed 55 people. The number went up yesterday when a victim died of injuries in a hospital.

Deputy Assistant Commissioner for terrorism Peter Clarke said the photo was being released in the hope of generating information about the bombers.

He also said that police can now officially name the men and state they are suspected of being the bombers. The information previously had been uncovered by news reporters.

In the photo, Hasid Hussain is in front. The 18-year-old would end up on the Route 30 double-decker bus. Police think the bomb in his backpack exploded at 9:47 a.m., killing him and 13 others.

Back at his home in the northern city of Leeds, his parents thought he was off for a weekend trip to London with friends. They could not reach his cellphone and worried that he might have been caught in the attack. Their call to Scotland Yard became central to the investigation, leading police to this single photo from 6,000 seized tapes.

Hussain's family and that of Germaine Lindsay, 19, the second in line in the photo, and Mohammad Sidique Khan, 30, who's third, said they had no clue as to what the young men were doing, or even that their Muslim faith had become radical and hateful. The other man in the photo is Shahzad Tanweer, 22.

Neighbors in Leeds described Lindsay, who had a pregnant wife and 16-month-old son, as an anti-U.S. radical. ABC television reported that the FBI was investigating whether Lindsay had ties to unnamed people in New Jersey.

Khan's family, (he is suspected in the Edgware Road blast that killed him and six others) said they wanted to express their "deepest and heartfelt sympathies to all the innocent victims and their families and friends affected by this horrific and evil act."

"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. We urge people with the tiniest piece of information to come forward in order to expose these terror networks which target and groom our sons to carry out such evils."

Meanwhile, the investigation continued in England, Egypt and Pakistan — where some of the bombers are thought to have gone for religious training.

British media reported that two to four men were being questioned in Pakistan about links to the four who appear in the photo. New Scotland Yard would not confirm that development.

Authorities in Islamabad said they questioned teachers and administrators at one of two religious schools thought to have been visited by one of the suspects.

Asad Farooq, a school spokesman, said agents had been there yesterday but denied that the suspect, Tanweer, had ever been at the school.

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

In Cairo, Egyptian police continued to question biochemist Magdy Mahmoud Mustafa el-Nashar, 33, who is believed to have rented a home to one of the bombers. Egyptian officials said they did not think he was connected to al-Qaida.

British Prime Minister Tony Blair said yesterday that the bombings were part of a war plan by radical Islamic terrorists.

"Senseless though any such horrible murder is, it was not without sense for its organizers," he said. "It is not a clash of civilizations — all civilized people, Muslim or other, feel revulsion at it. But it is a global struggle and it is a battle of ideas, hearts and minds, both within Islam and outside it."

Information from The Associated Press and the Los Angeles Times is included in this report.