Still, the raid opened fresh divides in Birmingham's predominantly Pakistani neighborhoods.
"People don't trust their own children any more," said Shabir Hussain, chairman of the Ludlow Road Mosque in Birmingham. "You feel like you should challenge your son or daughter: `Where are you going at night? What are you watching on TV? What are you doing on the Internet?'
Muslims in Birmingham are mindful of the dangers inherent in any raid: Police shot a man in a raid last year in London.
"The police and government seem to be against Muslims and are trying to turn us against one another," said Kadir Mohammad, 18, who lives in one of the raided neighborhoods.
Britain's MI5 has said it set up a network of eight new regional offices across the country in the wake of the Sept. 11 attacks, including a center in the West Midlands. The service had previously had regional branches in Northern Ireland, but uses the new offices to coordinate with police in counterterrorism work.
Counterterrorism experts said Islamic extremists have been looking for new ways to rattle the West with their use of the Web to broadcast propaganda and unsettling images such as the beheadings of Western hostages in Iraq.
One widely publicized case was that of 62-year-old Kenneth Bigley from Liverpool. He was abducted from a Baghdad suburb where he was working in September 2004 and beheaded three weeks later. His death was captured on video.
London's counterterrorism officers had never before dealt with a terrorist plot to abduct and murder, a police spokeswoman said on condition of anonymity because of the ongoing investigation.
The Irish Republican Army and other Northern Ireland paramilitary groups routinely conducted kidnappings, mainly for the purpose of extortion - often targeting family members of those with access to banks, British military installations and police stations.
"This would be the first case (in Britain) of Islamic extremists using kidnapping as a tactic - but these are not the first terrorist kidnapping threats to Britain. The IRA provided those," said former U.S intelligence officer Bob Ayers, now a security analyst based in London.