British police say they suspect the bombs that blew up on London's transport system last week were homemade from common household chemicals. The revelation comes as new reports say that police in Cairo arrested and are questioning an Egyptian biochemist sought in the probe into the London bombings.
Police sources say new evidence leads them to believe the London bombs were made from acetone peroxide, and not military-style explosives as first thought.
Police say traces of acetone peroxide have been found at one of the four bomb sites and at the home of one of the four suspected suicide bombers in the northern city of Leeds.
Acetone peroxide is the same type of compound used by the confessed British shoe bomber, Richard Reid, who tried to blow up a U.S.-bound jetliner in 2001 with explosives packed in his athletic shoes.
London police commissioner Ian Blair says investigators are urgently searching for those who supported the four bombers. "What we expect to find at some stage is that there is a clear al-Qaida link, a clear al-Qaida approach," Mr. Blair explained, " because the four men who are dead are in the sort of category of foot soldiers, so therefore what we've got to find is who encouraged them, who trained them, who is the chemist. Those are the things in which we are now so interested."
He says part of the investigation focuses on Pakistan, where at least one of the suspected bombers went for religious education.
Mr. Blair said the fact that at least three of the suspected bombers were British-born Muslims of Pakistani descent should shake Britain's Muslim community out of what he called their "sense of denial" regarding potential terrorists in its midst. "We need them to tell us who the preachers of hate really are, who are the recruiters of the vulnerable, and what changes of patterns occur in people's behavior. One of these young men apparently seems to have moved from a sort of cricket-loving, happy person to suddenly wearing long robes and being deeply interested in religion. Well, it doesn't mean that he's become a terrorist, but this one obviously has," he said.
Mr. Blair says he will meet British Muslim leaders in the coming days to discuss the issue, and he will suggest measures they can take such as setting up their own anti-terrorist hotline to gather tips on suspicious persons and activities.