Two years later, the FBI put out an urgent all-points bulletin for Shukrijumah, depicting him as one of al-Qaida's most well-trained, intelligent and deadly operatives. He was described as the ultimate "sleeper agent," intent on attacking the United States, possibly with weapons of mass destruction. Law enforcement officials and terrorism experts now believe Shukrijumah is one of a handful of young, street-smart leaders of al-Qaida handpicked by Khalid Shaikh Mohammed, the mastermind of the Sept. 11 attacks, to keep the terrorist network alive and humming in the face of U.S.-led efforts to unravel it.