Italian police say a prime suspect in last month's failed bombings in London was probably part of an amateur, improvised group, rather than a large terrorist network.

Police identified the suspect as Ethiopian-born Hamdi Isaac, saying he changed his name to Osman Hussain and falsely claimed Somali citizenship to gain asylum in Britain in the 1990s. The suspect, arrested Friday in Rome, is one of four men believed to have carried out the attempted attacks on London's transit system on July 21. Britain is requesting his extradition.

The three other suspects were arrested last week in Britain.

The failed attacks came two weeks after four bombers killed themselves and 52 others on the London transit system. British police are searching for anyone connected to either set of attacks. At least 18 people have been detained for questioning.

Some information for this report provided by AFP, AP and Reuters.