Al Queda USA

Are terrorist cells still in the US?

The homegrown nature of the July attacks in London as well as the arrest of a man in Zambia on charges that he'd tried to set up a terrorist training camp in Bly, Ore. in 1999, gives the questions extra salience, according to terrorism experts.

Their assessments of the law enforcement's success rate are mixed. Critics note that most of the suspected terrorists arrested in the US so far were not engaged in any active plan to harm the US. Some, like the newly charged paramedic Mahmud Faruq Brent, had allegedly gone for training in camps in Afghanistan or Pakistan, but mostly they were caught bragging to undercover agents - who openly encouraged them - about their willingness to engage in jihad.

At the same time, analysts point out that the nature of Al Qaeda has changed so much in the light of aggressive law enforcement tactics since 9/11 that the traditional "sleeper cell" model may no longer be attractive to al Qaeda here in the US. As a result, capturing potential terrorists may be the best thing the FBI can be doing right now.

"Measured against [FBI director Robert] Mueller's very confident assertion that there are hundreds of individuals who are members of sleeper cells in the US, these arrests don't indicate to me that we are making progress," says Michael Greenberger, director of the Center for Health and Homeland Security at the University of Maryland. "At the same time, I sympathize with the need to nip terror in the bud and it may very well be that indictments that focus on proposed activities or bragging about future activities may be effective. But we also have to wait to see what the facts in each case were."