LONDON — Police yesterday sought a U.S.-educated chemical engineer thought to have made the bombs for last week’s terrorist bombings, along with another suspect with reported links to al Qaeda whom they think masterminded the deadly attacks.
Authorities also broadened their investigation to include a macabre hypothesis that the four suicide bombers sought to form a burning cross in London’s subway — with the King’s Cross station as the center — to symbolize an Islamic strike at the heart of a Christian nation.
Police sources named Magdi el-Nashar, an Egyptian chemical engineer who once studied at North Carolina State University and more recently lectured at Leeds University as the suspected bomb maker.
El-Nashar vanished days before the July 7 attack.
One week after at least 54 persons, including the four bombers, were killed, evidence pointed to an attack planned in meticulous detail at both the ideological and operational level — a trademark of past strikes by Osama bin Laden’s al Qaeda network in its war against the West.
Progress in the investigation came as Britons filed into the streets in a silent tribute — broken only by the noon chimes of Big Ben — to those killed and injured in the bombings of three subway trains and one bus.
Hoping to jog public memories, police handed bus and rail passengers a dramatic photograph of one of the attackers, the bomb strapped to his back in a military-style rucksack, en route to blow himself up on the No. 30 bus and kill 13 passengers.
Police also continued to search properties in northern England, where they found additional bomb-making materials.
Forensic experts found explosives in el-Nashar’s apartment in Leeds and army bomb-disposal experts found additional material in a blue-fronted bookshop frequented by the suicide bombers.
The chemist’s neighbors said young men would come in and out of el-Nashar’s apartment at odd hours of the night, and the landlord, Samir Al-Arni, said el-Nashar had insisted on all the furniture being removed when it was rented just three weeks earlier.
One neighbor told reporters that el-Nashar “spent time in Pakistan and in Afghanistan where he was trained in army-type activities. But I never thought he would bomb in Britain. I thought he was just an odd fish.”
El-Nashar’s name came to light when police found his number in the phone memory of bus bomber Hasib Hussain’s mobile phone.
U.S. law-enforcement authorities said el-Nashar enrolled for a chemical-engineering course at N.C. State in Raleigh in January 2000, but left the school shortly thereafter to return to Britain and enrolled as a graduate student at Leeds University.
N.C. State officials said that FBI agents were at the school yesterday seeking information on el-Nashar and that “all the files” on the former student were turned over to the agents.
FBI spokesman Stephen Kodak declined “to comment on a British investigation.”
Also, yesterday the Associated Press identified the fourth attacker as Jamaican-born Briton Lindsey Germaine.
The “burning cross” hypothesis arose from the bombers’ intention to travel in four directions from the hub, King’s Cross station.
“The name itself may be significant, containing ‘cross,’ ” said an investigator, who refused to be identified.
“They could have blown themselves up in any four rail-cars on their train journey down, or an any metro line. Instead, they chose trains running north, south, east and west. We think it was intended as an al Qaeda message — to seemingly blow up in the form a fiery cross in the heart of the Christian infidels.”
The fourth bomber climbed onto a bus because the Northern Line train that he was planning to board was delayed by technical problems, the investigator said.
Even the claim of responsibility the day of the attack by a group calling itself the Secret Organization Group of al Qaeda Jihad Organization in Europe lent credence to the hypothesis.
“Now, Britain is burning with fear, terror and panic in its northern, southern, eastern and western quarters,” the previously unknown terrorist group said.
Propaganda video footage of an al Qaeda training camp shows terrorist trainees firing at crosses.
Although a burning cross is usually associated with the racist Ku Klux Klan in the United States, it recently has been adopted by militant Muslims.
During a May protest over reports that U.S. interrogators had desecrated the Koran during interrogations at Guantanamo Bay, a group of Muslims burned a cross in front of the U.S. Embassy in London.
“The Islamists see the cross as a symbol of infidelity that has to be destroyed or its followers have to be subjugated,” said Dr. Taufiq Hamid, a physician who was part of an extremist Islamic group in Egypt but who now strongly opposes the militants.
The second at-large suspect, thought to have been the mastermind, is said to have arrived in England by ship only three weeks ago and to have fled the country the day before the bombings.
Police sources say they think he had links with a terrorist suspect being held in the United States and had associates connected with bin Laden. They declined to elaborate.
A security source said he may or may not have been “Mr. Big, the organizer with the expertise who made it happen. Our greatest fear is that the mastermind has trained other suicide bombers.”
Jerry Seper contributed to this report in Washington.