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.
Creating the Image of a Killer
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.
A Descent Into Psychosis
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.
"I think he's experiencing that, but he does not understand it and projects it on the world instead."
Many Questions Still Unanswered
What the newly released tape and pictures do not answer is the question of why -- what could have driven Cho to go on his rampage?
Dr. Kathyrn Moss, attending psychiatrist in the Personalities Disorders Clinic at NewYork-Presbyterian/Weill Cornell, said it is unlikely that one factor alone led to Cho's behavior.
"This is a mix -- a constellation of factors that came together in a horrific way," Moss said. "It's not just one thing. It can't be."
Ragan agrees. "Usually behavior is multideterminant, meaning there's not just one thing behind it," he said.
"There are a number of elements that come together that create a situation -- and there was the perfect psychological storm to create this enormous tragedy."
Among the possible contributors to Cho's mental state could have been an underlying mental condition and a background of violence.
The tape sheds little, if any, light on the exact causes, however.
"One question I have is: Where does this preoccupation with violence come from?" Ragan said. "He is obviously enamored with weapons and violence. It is totally bizarre, the pose with the hammer. Obviously he's very serious, but he's pretty crazy."
Williams said abuse in early life can sometimes result in violent behavior later, though no such abuse has yet been found in Cho's situation.
"It is well known that men who were abused -- emotionally, physically and/or sexually -- as children are far more likely than those not abused to engage in violent behaviors as adults," Williams said.
"This makes it important to search very carefully in Cho's history, to see if there is any evidence he was abused. If so, it would help to explain how he developed into a young man with tendencies to anger and aggression."
Tendencies that would eventually lead Cho to submit to the world a terrible glimpse into his fractured psyche.
"Clearly it's a horrible way to do it," Ragan said. "It is a fusion of the egomaniacal and the criminal, and there is an absolute absence of any kind of regard for the enormous harm this inflicts on others."