Informant thwarts bomb plot

WILLIAMS: Good evening.

BRIAN WILLIAMS, anchor: We are now learning more about a foiled plot to blow up an airliner bound for the US. Again, thankfully it was disrupted before it got very far. And it now turns out that the bomber was actually an informant cooperating with intelligence services friendly to the United States . This case has raised a lot of issues all over again about our airline security , about how strong al-Qaeda still is these days, and about how many more of these could be out there. It's where we begin tonight with our justice correspondent Pete Williams in our Washington newsroom. Pete , good evening.

PETE WILLIAMS reporting: Brian. And by all accounts, this is a remarkable success for the intelligence agencies of the United States and its allies. And here's why. They managed to insert a critical informant into the very heart of the terror group that's considered the number one threat to the United States , al-Qaeda 's offshoot in Yemen . Administration and intelligence officials say by the time this most recent plot was in its final planning stages, the US and its allies were able to follow it in detail. What the terrorists in Yemen did not know at the time, these officials say, is that the person they chose to be the suicide bomber was actually an informant, someone who had agreed to cooperate with an allied intelligence service . Members of Congress declined to be specific but praised the CIA and its overseas counterparts.

Representative PETER KING (Republican, New York): This was incredibly good intelligence work. I mean, this is intelligence at its best.

P. WILLIAMS: After the al-Qaeda operatives turned over the finished the bomb, the informant then drove it safely out of Yemen , where it was eventually turned over to the United States .

Secretary JANET NAPOLITANO (Homeland Security Secretary): I want to say that the device was always under control, and that no one in the United States was ever at risk because we did have control.

P. WILLIAMS: Those who have seen the bomb say it is remarkably similar to this, the one worn by the 2009 Underwear Bomber . While the ingredients were improved, they say, intended to be more reliable, the overall design was basically the same, with no metal, presenting no more challenge to screeners than the 2009 underwear bomb. As a result, US officials say, no change in airport security is planned.

Senator CHARLES SCHUMER (Democrat, New York): The fact that we have the device shows us what to look for, and how to detect such devices should they try to be used in the future.

P. WILLIAMS: But could it have gotten through screening? Homeland Security officials say they cannot be certain, but just as with the 2009 underwear bomb, they're optimistic the answer is no, caught either by the full-body scanners and pat-downs or by a combination of screening, passenger information and other intelligence .

Sec. NAPOLITANO: In today's date with all the various layers we have, in all likelihood, it would not have succeeded.

P. WILLIAMS: The Obama administration and members of Congress from both parties say they will investigate how word of this top secret intelligence operation first began to leak last week before it was made public. They say that put at risk those involved in disrupting the plot. Brian :

B. WILLIAMS: All right, Pete Williams starting us off from Washington tonight.