The Terrorists Next Door

Like most Londoners, residents of the Peabody housing estate have become used to seeing cops on the street, reminders that their city is under threat. The war came home last week. "We won't hurt you!" a group of armed police shouted to men sheltering inside a fourth-floor apartment in a block of red-brick buildings. The officers had staked out the complex for hours, believing that two of the men wanted for the unsuccessful attempt to bomb the city's transportation system on July 21 were hiding inside. When the suspects failed to give themselves up, witnesses say, the officers stuck a strip of plastic explosive around the edge of the apartment door and blew it off. A bare-chested man emerged, his arms in the air, and was led away. Police fired tear gas into the house, and two more shirtless men appeared on the balcony, vomiting and spitting from the gas. To ensure that the men could not detonate themselves, the police told them to remove their pants, then hauled the suspects away.

Beamed around the world, the raid in west London was the most dramatic confrontation yet between British authorities and Muslim extremists since four of them detonated bombs during the morning rush hour on July 7, killing 52. The perpetrators perished with their victims, but the arrests last week of all four suspects in the failed July 21 bombing--who apparently had intended to inflict carnage on a comparable scale--provided a measure of relief to a jittery city. In Birmingham, in the center of England, police snared Yasin Hassan Omar, allegedly the man shown on closed-circuit-television tapes who was planning to bomb the Warren Street underground station. The Peabody bust netted Ibrahim Muktar Said, suspected of trying to bomb a bus in east London, and Ramzi Mohammed, who fled from the Oval station after allegedly leaving a bomb. And in Italy, authorities announced they had caught Osman Hussain (also referred to as Hussain Osman by British police), who is alleged to have tried to blow up a train at the Shepherd's Bush tube stop.

"The investigation has moved with some speed," British antiterrorism-police chief Peter Clarke said Friday, "but it is still continuing." Nonetheless, a lot of loose ends remain. Despite the spectacular arrests, the review of more than 35,000 closed-circuit-television tapes and more than 5,000 leads phoned in by the public on the antiterrorist hot line--police have asked people to program the number into their cell phones--investigators don't have a clear understanding of the dimensions of the twin terrorist plots. British and U.S. officials told TIME that police have not found any forensic link between the July 7 and July 21 bombers--no phone calls, documents or other evidence tying the two groups together. Contrary to earlier speculation, the bombs used on July 7 and July 21 came from different batches of homemade explosive, says a British official, which means either the same "chemist" made different batches or more than one chemist is still on the loose. It remains unclear how--or even whether--each team is linked to al-Qaeda, and this raises the chilling specter of multiple jihadist cells operating on their own. A U.S. counterterrorism official says the British and U.S. governments are open to the idea that the two attacks "may have been planned independently of each other."