Psychological experts say the video that Virginia Tech student Seung-Hui Cho shot of himself sweeps away any grain of doubt about his disturbed state of his mind.
The video, which Cho mailed to NBC News in a two-hour hiatus during Monday's horrific shooting spree, features a violent and disorganized diatribe which psychological experts say offers a glimpse into a mind twisted by psychosis and rage.
"It's now really clear that he was suffering severe mental illness at the time of the rampage," said Dr. Redford Williams, director of Duke University's Behavioral Medicine Research Center in Durham, N.C.
"It appears that this was not schizophrenia, but some form of severe mental illness accompanied by paranoid delusional thinking, as reflected in his rantings on the video about people with trust funds and cognac and vodka."
"In his twisted, psychotic mind, this was clearly another way of inflicting more damage -- in this case through psychological means," said Dr. Paul Ragan, associate professor of psychiatry at Vanderbilt University Medical Center.
"It's kind of devious, and it suggests that along with his psychosis, there are also clear psychopathic elements there."
But psychologists say the very fact that the tapes were sent -- and Cho's violent grandstanding -- may reveal much more about his motivations and state of mind than the messages he relays in the tape itself.
The aggressive, pistol-brandishing persona Cho adopts in the video and pictures he produced is a stark diversion from the quiet outcast described by his roommates and professors.
Dr. Michael Welner, chairman of The Forensic Panel and professor of psychiatry at New York University, said the dramatic attitude Cho adopts in his tape and photographs was likely a façade.
"This is not him," Welner said. "These videos do not help us understand him. They distort him. He was meek. He was quiet.
"This is a PR tape of him trying to turn himself into a Quentin Tarantino character."
Ragan agrees that the video was likely an exercise in egomaniacal behavior.
"Clearly, self-absorption is overwhelming," he said, noting that Cho was likely pursuing a certain kind of grandiosity.
The disorganized nature of what some are calling Cho's "manifesto" may give additional hints at the progression of his mental illness.
"I think that the word 'manifesto' is a misnomer in this case," Ragan said. "His rantings are pretty disorganized. But he is clearly, clinically speaking, a very angry, enraged person."
Ragan adds that though it is impossible for him to definitively diagnose Cho from just the evidence on the tape, the video, when considered alongside his disturbing writings, indicates a gradual descent into psychosis.
"He wrote the plays, and he was clearly trying to gain expression there," he said. "When he switched to video, this rage went to a larger scale and was more primitive. At least the plays had some structure.
"We see a disconnection from reality, as well as projection -- 'You have blood on your hands,' as well as the nonlogic of the rant."
Ragan said Cho's remarks that he had been "cornered" could also shed light on his deteriorating mental state in the weeks and months before the incident.
"He expressed a feeling that he was cornered, which is interesting," he said. "Often, psychosis is not an all-or-nothing proposition. Sometimes it starts small and expands.