No Direct Evidence of Plot To Attack Around Elections

New security precautions include the closing of the 15th Street sidewalk beside the Treasury Building, forcing pedestrians to walk on a traffic lane. (Jonathan Ernst For The Washington Post)

At the FBI, about 2,000 counterterrorism agents have been assigned the task of conducting interviews and following up on leads, with instructions to report to 24-hour call centers in each field office. The disruption plan "is intense up to the election, but they're keeping command posts operational for longer than that," one official said.

The person in charge of the campaign is Patrick Cook, who was summoned to FBI headquarters the day after Bush's briefing, officials said. Reassigned on the spot from his job as a senior official in the Washington field office, Cook moved to the FBI's Strategic Information Operations Center with a mandate to run the national disruption plan.

"They told him his whole job is to prevent an attack before the inauguration," said a sympathetic colleague who works elsewhere. "Which is like being told, 'Make the sky turn purple.' "

The FBI's approach depends on "tripwires" to detect suspicious activity. The system, implemented last year and based on the behavior of the 19 Sept. 11 hijackers, generates alerts if a known subject buys an airline ticket, rents a car or applies for a driver's license -- in his or her own name. The national criminal information database, consulted routinely when local police make a traffic stop, is now capable of sending a "silent hit" to the bureau if the driver is on a watch list.

"If they follow the model of the 19 [hijackers], we'd detect them, I can tell you that," said a high-ranking law enforcement official, who added that he is unable to discuss the screening methods in public.

The FBI and other agencies have also performed exhaustive searches of records on explosives permits, rental storage facilities, crop-dusting airplanes and other specialized areas that have been identified as potential targets of al Qaeda.

Yet law enforcement and intelligence officials frankly acknowledge that their information is limited. "People are so terrified because they can't see clearly anymore," a government counterterrorism analyst said. Because of the success in closing al Qaeda's sanctuary in Afghanistan, the analyst said, "we can't see the training camps, we've driven their communications further underground, and the operators have effectively disappeared."

Even as the government intensified its campaign, authorities discovered that one of the CIA sources they had relied on had fabricated his story, according to several counterterrorism officials. One intelligence official said the revelation "caused us to go back to square one and reassess where the plotting really is."

Other officials, however, played down the source's importance. "It's thought that what he had said was pure misinformation" designed to mislead the government, a different intelligence official said. But, the official added, that did not increase anyone's comfort level, because there are many other sources indicating that al Qaeda wants to launch an attack.

FBI and Justice Department officials said they are still keenly worried about the whereabouts and activities of seven fugitives who were named in May as possible suspects in the planning of an al Qaeda attack. One person of particular concern is Adnan G. el Shukrijumah, a Saudi-born radical raised in Guyana and the United States who has been identified as a valued operative by Khalid Sheik Mohammed, the al Qaeda lieutenant who is in U.S. custody.

Shukrijumah, 29, is a trained pilot who lived in Florida until he fled after the Sept. 11 attacks. He has a $5 million U.S. bounty on his head. U.S. authorities have linked him to numerous possible plots, including an abandoned scheme with U.S.-designated enemy combatant Jose Padilla to blow up U.S. apartment buildings with natural gas. The FBI has fielded numerous reported sightings of him from Morocco to Central America, but none has been confirmed.

"A number of the detainees, when asked 'Can you think of who would be sent to the U.S. for an attack?,' " have named Shukrijumah, a terrorism analyst with the government said. "He's a real threat. He speaks Spanish, English and Arabic; he's totally bought into the plan, and nobody -- but nobody -- knows where he is."

A key component of the disruption plan has focused on scrutinizing immigrants for violations. Among those arrested by Homeland Security in recent weeks was a 28-year-old Saudi who had dropped out of a U.S. university after enrolling last year, according to a news release from the department's Immigration and Customs Enforcement (ICE) bureau. The student, who was not identified, was stopped last year while trying to carry a stun gun onto a U.S. airliner, the release said.

Another former student, a 24-year-old Lebanese citizen, had his visa revoked by the State Department for national security reasons, the release said. He was working in a convenience store and was no longer in school, according to the release. It did not say where the former students were living.

The arrests were made by ICE's Compliance Enforcement Unit, which flagged the suspects with the help of three new systems for tracking visitors: a student database, a system for identifying arriving and departing foreigners, and a program that requires men from two dozen mostly Muslim countries to register.

Not all of the 120 arrests involved security risks. One of those listed, for example, was a South African woman who entered the country this year on a student visa but never enrolled. She was arrested and placed in deportation proceedings but was released with an electronic monitoring bracelet, the news release said.

Staff writers John Mintz and Mary Beth Sheridan contributed to this report.