WP: Probe Rooted In Attacks on Transit System

[Rose Siding]

It all began with a tip: In the aftermath of the July 7, 2005, suicide bombings on London's transit system, British authorities received a call from a worried member of the Muslim community, reporting general suspicions about an acquaintance.

From that vague but vital piece of information, according to a senior European intelligence official, British authorities opened the investigation into what they said turned out to be a well-coordinated and long-planned plot to bomb multiple transatlantic flights heading toward the United States -- an assault designed to rival the scope and lethality of the Sept. 11, 2001, hijackings.
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One U.S. intelligence source, however, said some of the British suspects arrested had made calls to the United States.
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Counterterrorism officials said the basic outline of the conspiracy was known for several months. Investigators from New York to Islamabad, Pakistan, said they were briefed by their British counterparts late last year....

Some U.S. counterterrorism officials said plans originally were to allow the conspiracy to develop even further. But U.S. and British investigators made a sudden decision this week to close down the operation after they became increasingly worried that there were other bombers they had been unable to locate or identify, U.S. officials said.

http://www.washingtonpost.com/wp-dyn/content/article/2006/08/10/AR2006081001654.html