Conspiracy theories are common after traumatic events. Michael Barkun, a political scientist at Syracuse University who has written books on the culture of conspiracies, said contradictory and inconclusive eyewitness accounts often leave room for different interpretations of events.
"Conspiracy theories are one way to make sense of what happened and regain a sense of control," Barkun said. "Of course, they're usually wrong, but they're psychologically reassuring. Because what they say is that everything is connected, nothing happens by accident, and that there is some kind of order in the world, even if it's produced by evil forces. I think psychologically, it's in a way consoling to a lot of people."
The belief that the government is lying about the Sept. 11 attacks is coming from both the right and the left. Experts say more than suspicion of the Bush administration is at work.
"It seems that since the end of the Cold War, the enemy is the United States government, the enemy is within," said Rick Ross, whose Ross Institute of New Jersey monitors cults and other controversial groups, many of which see manipulative forces working behind the scenes. "Instead of projecting conspiracy theories out, it's become internalized."
Zelikow, for example, lacks credibility with many who question the work of the 9/11 commission because he wrote a book with national security adviser Condoleezza Rice. He believes that it is futile to discuss evidence with people convinced of a conspiracy.
"The hardcore conspiracy theorists are totally committed," Zelikow said. "They'd have to repudiate much of their life identity in order not to accept some of that stuff. That's not our worry. Our worry is when things become infectious, as happened with the [John F. Kennedy] assassination. Then this stuff can be deeply corrosive to public understanding. You can get where the bacteria can sicken the larger body."
David Ray Griffin considers himself an unlikely recruit to what is called the "9/11 Truth Movement." The retired theologian, who taught religion for three decades at Claremont School of Theology, initially dismissed the notion that it was not an airliner that hit the Pentagon. But after visiting several Internet sites raising questions about the attack, he ended up writing a book. "The New Pearl Harbor," published in the spring, argues that a Boeing 757 would have caused far more damage and left more wreckage strewn around the Pentagon.
"There are reasons why people doubt the official story," he said. "There are photographs taken, and there is no Boeing in sight."
Suspicions formed as the Pentagon still smoldered.
For 2 1/2 years, the attack on the Pentagon has been discussed and researched by members of Knight-Jadczyk's online group, the Quantum Future School.
The group's talks formed the basis for articles in which Knight-Jadczyk argues that after the attack on the World Trade Center, eyewitnesses at the Pentagon were predisposed to see a large airliner. She believes that the Pentagon was attacked by a smaller plane and that members of the Bush administration were somehow complicit because it was beneficial for war-profiteers and Israel.
Interviewed by telephone from what she said is a 17-bedroom castle outside Toulouse, where she lives with her Polish physicist husband and five children, Knight-Jadczyk acknowledged that her group is considered "fringe."
Knight-Jadczyk, 52, a Florida native, has been a psychic and a channeler. She is now involved in experiments in what she calls "superluminal communication," which she described as involving "time loops" that would enable people to communicate with their former selves.
Knight-Jadczyk said she never imagined anyone outside her group would ever view "Pentagon Strike."
"The fact everybody's been sending it to his brother and his cousin, almost frenetically, reflects the fact that there is a deep unease," she said. "They don't come out and say it. They don't want to be accused of being with terrorists, anti-American or anti-patriotic. But they still feel something's wrong."
Bret Dean of Fort Worth said he considers it "baloney" to question whether a plane hit the Pentagon. But he also believes that the government ignored warning of the attacks.
After posting a link to the video on his libertarian site, www.freedomunderground.org, Dean recorded more than 8 million hits. At least one came from inside the Defense Department, he said.
"I don't think the video is an instigator," said Dean, 45, a former casino worker. "It's a symptom. A lot of people don't trust the government's explanation because the government's classified all the information."
Asked if there were unreleased photographs of the attack that would convince the doubters, Zelikow, of the 9/11 commission, said, "No."
"The question of whether American 77 hit the Pentagon is indisputable," Zelikow said. "One reason you tend to doubt conspiracy theories when you've worked in government is because you know government is not nearly competent enough to carry off elaborate theories. It's a banal explanation, but imagine how efficient it would need to be."