Police today grilled four suspected London suicide bombers, a day after three of them were nabbed in a dramatic fashion in west London and one in Rome, in connection with the July 21 failed bombings.
Police sources said they believe that all four members of the gang behind the attacks are now in custody.
Alleged failed bus bomber Muktar Said-Ibrahim, 27, and a man calling himself Ramzi Mohammed -- suspected of attempting the Oval tube bombing -- were captured in raids in west London Friday afternoon.
Police also arrested Wahbi Mohammed, 23, brother of Ramzi Mohammed, at a raid in Tavistock Crescent. A day earlier, a fourth suspected bomber, Yasin Hassan Omar, 24, a Somali citizen with British residency, was arrested in Birmingham.
In Rome, Osman Hussain, 27, said to be the would-be bomber of a train at Shepherd's Bush, west London, was answering interrogators' questions today, Italy's interior minister Giuseppe Pisanu said, as police fanned out across Italy to check the man's contacts.
"We are facing a grave threat which must be dealt with all means of prevention and crackdown that we have," the Interior Minister said.
He was giving the first details of Friday's arrest of Hussain Osman following a manhunt from England to Italy. Pisanu said Osman, a Briton with Ethiopian citizenship, left Britain on July 26 by train from Waterloo station, the terminal for Eurostar which carries passengers from Britain to several destinations in mainland Europe.
Italian police conducted 15 searches across the country based on the suspect's contacts. "Important investigations are being conducted in Venice, Salerno and other cities," Pisanu said.
Investigators wanted to know how the suspect made his way to Rome. He was arrested at an apartment on the capital's outskirts reportedly belonging to his brother.
Police with bomb-sniffing dogs searched the apartment for hours last night.
Milan daily Corriere della Sera today reported that two maps of the Paris subway system were found in the apartment, but it was not clear whether the suspect might have used them as part of his flight or if they figured in any attack plans.
Newspapers said investigators suspected Osman's real name was Hamdi Isaac. His brother in Rome is Remzi Isaac, Corriere said.
Meanwhile Peter Clarke, head of the anti-terrorist branch of London's Metropolitan Police said Britain would ask Italy to extradite Osman.
According to the Milan daily, investigators are almost certain that Osman traveled entirely by train after fleeing London.
Reports said his use of a relative's mobile phone throughout his flight was crucial in helping police track him down. Mobile phones linked to a regular account can be easily traced.
British secret services told French and Italian investigators that Osman was using an English mobile phone belonging to a brother-in-law.
According to the report Osman spoke fluent Italian. Besides a brother in Rome, he has his father in the northern Italian city of Brescia.
But Pisanu said that the Ethiopian father of the suspect's fiancée lived in Brescia, and that Osman had contacts with others from the Horn of Africa in Milan and Brescia.
Police in Rome said Osman was born in Ethiopia on July 23, 1978. British police were investigating how Osman Hussain managed to get out of Britain five days after the failed attacks, despite a huge manhunt and his photograph being issued to officials at all ports and airports.
London has been on edge since four suicide bombers attacked three subway trains and a bus during rush hour on July 7, killing 56 people.
The failed attacks two weeks later took no lives but were a stark indication that the terror threat is not over.
Scotland Yard described yesterday as their "best day yet" in the hunt for the July 21 bombers. But Peter Clarke, the head of Scotland Yard's anti-terrorist branch, said that "the threat remains, and is very real."
"We must not be complacent," Clarke said.