..."Phoenix memo" last summer warning about that Arab students training at U.S. aviation schools were linked to a militant Muslim group.In addition, Williams' memo had identified another Muslim figure in Arizona — who was not training at aviation schools but was linked through phone communications to one of bin Laden's top lieutenants, Abu Zubaydah, the officials said, speaking only on condition of anonymity.
The agent spent extensive time trying to link that man to one of the students, but never succeeded, officials said.
The officials declined to further describe the communications or the man who contacted Abu Zubaydah, citing concerns about protecting intelligence-gathering methods.
Abu Zubaydah is believed to be bin Laden's operational chief, who ran al-Qaida's terrorist training camps and is suspected of helping organize the Sept. 11 hijackings, U.S. officials have said previously.
Abu Zubaydah was captured by the FBI and Pakistani officials during a raid in March and remains in U.S. custody. During interrogations, Abu Zubaydah has alleged several threats against U.S. targets that have prompted protective warnings, officials say...