Pieces Of The 9/11 Puzzle
U.S. spies knew about `Khalid'--but they didn't know he was here
Despite the conventional wisdom that America's intelligence agencies closely monitor international calls to and from the United States, the NSA was exceedingly leery of eavesdropping by accident on what it calls "U.S. persons," who include American citizens and others inside the United States. NSA analysts have had the authority to listen to calls involving U.S. persons if they come into contact with suspected terrorists overseas, but they are not allowed to specifically target Americans. The FBI is also authorized to monitor and trace calls between people in the United States and abroad, but the congressional 9/11 inquiry faulted both agencies for failing to coordinate and plug holes in the coverage. "It was NSA policy to avoid as much as it could any coverage of individuals in the United States," says Hill. "That would have been fine as long as we ensured that the FBI was following up on those areas."
Hill's inquiry found that neither the NSA nor the FBI took full advantage of provisions of the Foreign Intelligence Surveillance Act that would have helped them target such communications--including the targeting of individuals rather than simply individual telephone numbers. Aggressive use of this technique, the inquiry concluded, might have detected al-Mihdar and others earlier. U.S. officials, however, defend their procedures. "If we became aware they were calling for pizza in the United States, we would have called the FBI," insists one of the Bush administration's most senior intelligence officials. "We didn't know."
Still, the episode exposes surprising limitations in America's oft-touted global eavesdropping ability. At the heart of the effort stands the NSA, which controls a massive array of satellites, listening devices, and supercomputers that capture all kinds of foreign electronic signals from telephone calls to missile telemetry. In reality, the NSA is drowning in information, and every day is a constant struggle to process and make sense of the enormous volume of calls it intercepts, intelligence experts say. In many cases, NSA analysts start off with only the identity of a person on one end of the phone call. Sometimes, intercepts pick up only fragments of a conversation.
In the case of the calls to and from the house in Yemen, there were technological limits to what U.S. eavesdroppers could pick up. "Neither the contents of the calls nor the physics of the intercepts allowed us to determine that one end of the calls was in the United States," says the senior intelligence official. It was only after 9/11, prompted by the congressional inquiry, that the FBI delved into toll records and found the U.S. origin of al-Mihdar's calls. In other words, it would have taken initiative on the part of the FBI or other agencies to trace some of the hundreds of phone calls in and out of a target site like the Yemeni house. "NSA did not think it was its job to initiate this research on its own," according to a staff statement by the current 9/11 commission. "It tends to wait to be asked."
The FBI was overwhelmed, as well, and many good leads were simply overlooked as agents tried to cope with the stacks of NSA reports they routinely received. Veteran agents also point out that the Yemen safehouse was one of numerous facilities U.S. intelligence agencies were monitoring. "The amount of data was overwhelming," says Sheila Horan, a former senior official in the FBI's national security division. "When you have a limited number of analysts and agents, you can't possibly cover all those intercepts."
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