Officials Consider Al Qaeda Infiltration

W A S H I N G T O N, Aug. 4, 2004 -- U.S. intelligence has evidence al Qaeda operatives cased major targets in New York and Washington from the inside, ABC News has learned. It was part of a meticulous surveillance operation that managed to obtain unusual access.

Information found on the computer files of Mohammed Khan, the 25-year-old computer engineer who was arrested last month in Pakistan, is responsible for the current terror alert at financial centers in New York, Washington, D.C., and Newark, N.J.

Khan's records continue to yield critical clues about al Qaeda's operations, including indications that he may have communicated with several people in the United States in recent months, sources told ABC News.

Khan's computer files show al Qaeda operatives thoroughly casing the financial centers both outside and inside just before the attacks of Sept. 11, 2001, the sources said.

Law enforcement officials said the bulk of the extensive surveillance was conducted on the Citigroup Center in Manhattan, the International Monetary Fund and World Bank buildings in Washington, and Prudential Financial Inc.'s headquarters in Newark, N.J. Federal officials publicly identified those targets earlier this week, along with the New York Stock Exchange.

"Given the specificity that apparently are in these reports, that they were not just casual targets. These were real targets," said former FBI counterterrorism agent Jack Cloonan, an ABC News consultant.

The computer files, written in English, narrate the travels of al Qaeda members throughout the buildings, offering step-by-step color commentary in rich detail, sources said.

The documents suggest the facilities were under surveillance morning and night, with operatives looking for times when security was lax and when the most potential victims were present.