Authorities appear to have been looking for evidence of direction from overseas or communication involving a developing plot, Hoekstra said. "They're looking for somebody to say, 'Go,' " Hoekstra said.
"But I don't think that's the kind of organization (al-Qaida) is trying to set up. They're more in the world of: 'If you see an opportunity, take advantage of it, and you don't have to get it approved at headquarters.' "
The federal official defended the bureau's handling of the matter. "The process worked," the official said. "It was evaluated by one JTTF and sent to another JTTF based on what information they had at the time. More investigation was done, and ultimately a judgment was made that" it did not merit further investigation.
Authorities continue to pore over Hasan's e-mails and other information to see who else he contacted and whether authorities dropped the ball by not continuing to investigate Hasan.
"If we find in his e-mails that he reached out to all kinds of other people for input," that assessment could change, said the official. "We just don't have the full context yet."
Hasan appears to have surfaced on U.S. surveillance inadvertently. The National Security Agency eavesdrops on electronic communications around the world, and routinely monitors the e-mails and calls of figures such as Awlaki.
The emerging details are likely to draw parallels with intelligence breakdowns that preceded the Sept. 11 attacks, when the CIA, NSA, FBI and other agencies failed to recognize or share information that may have helped uncover the plot.
Fixing those problems was the focus of a sweeping overhaul of the U.S. intelligence community.
Congressional investigators "are going to be taking a look at all of the information and making decisions on whether people should have been notified along the way," said a congressional official who has been briefed on the Hasan probe. "I think that's going to depend on the nature of the communications."
The Senate's Homeland Security oversight committee said it will investigate the shootings and what authorities knew about Hasan's possible motives and his connections to radical Islamists, either online or in person.
The committee will hold its first hearing next week, an unusually quick turnaround for such a public second-guessing.
Hoekstra sent a letter to the heads of the FBI, the CIA, the Directorate of National Intelligence and the National Security Agency directing their agencies to preserve all documents and materials "relevant to the Fort Hood attack and any related investigations or intelligence collection activities."
On his Web site, Awlaki frequently counsels his followers in what is acceptable under Islamic law. He has authorized acts of violence, including terrorist acts, under Islamic law by saying they were done to defend Muslims around the world from Western governments bent on destroying Islam.
Tribune Newspapers reported that soon after midnight Monday, after Awlaki's name was publicly linked to Hasan's, a posting on his Web site was titled "Nidal Hassan Did the Right Thing."
A second official said, "There are indications that contacts were attempted, but that doesn't mean that we've got a full-fledged al-Qaida network here trying to attack the military."
Officials emphasized that there is no evidence that Hasan received direction or input on his plan in the days or months before the attacks, in which he fired off more than 100 rounds from a pair of semi-automatic handguns, killing 13 and injuring 29 others.
Via McClatchy-Tribune News Service.