Seung-Hui Cho, the student who killed 32 people and then himself yesterday, left a long and "disturbing" note in his dorm room at Virginia Tech, say law enforcement sources.
He also wrote at least two violent plays for an English course that worried his professor and several classmates.
Sources described the note, which runs several pages, as beginning in the present tense and then shifting to the past. It contains rhetoric explaining Cho's actions and says, "You caused me to do this," the sources told ABC News.
Sources say Cho, 23, killed two people in a dorm room, returned to his own dorm room where he re-armed and left the note, then went to a classroom building on the other side of campus. There, he killed 30 more people in four classrooms before shooting himself in the head.
Witnesses say he was stone-faced as he opened fire. Law-enforcement sources say he may have had a romantic interest in a young woman who was found dead after the first shootings.
Lucinda Roy, a co-director of the creative writing program at Virginia Tech, taught Cho in a poetry class in fall of 2005 and later worked with him one-on-one after she became concerned about his behavior and themes in his writings.
Roy spoke outside her home Tuesday afternoon, saying that there was nothing explicit in Cho's writings, but that threats were there under the surface.
Roy told ABC News that Cho seemed "extraordinarily lonely--the loneliest person I have ever met in my life." She said he wore sunglasses indoors, with a cap pulled low over his eyes. He whispered, took 20 seconds to answer questions, and took cellphone pictures of her in class. Roy said she was concerned for her safety when she met with him.
She said she notified authorities about Cho, but said she was told that there would be too many legal hurdles to intervene. She said she asked him to go to counseling, but he never did.
One play attributed to him, called "Richard McBeef," describes a 13-year-old boy who accuses his stepfather of pedophilia, and ends with the boy's death.
In another, called "Mr. Brownstone," three high-school students face an abusive teacher.
"I wanna kill him," says one character.
"I wanna watch him bleed like the way he made us kids bleed," says another.
The two plays were posted on AOL after a staffer named Ian MacFarlane, a December 2006 graduate of Virginia Tech, brought them to his editors' attention.
MacFarlane said he was in a class with Cho in which students were required to post their plays online for peer review and comment.
AOL editors verified the authenticity of Cho's works before posting them, according to Alysia Lew of AOL Corporate Communications.
At a late-afternoon news conference, police said they had searched Cho's dorm room. "There were considerable writings that were reviewed," said Col. Steven Flaherty, Superintendent of the Virginia State Police.
Some news accounts have suggested that Cho had a history of antidepressant use, but senior federal officials tell ABC News that they can find no record of him in the governments files on controlled substances. This does not completely rule out prescription drug use, including samples from a physician, drugs obtained through illegal Internet sources, or a gap in computer databases, but the sources say theirs is a reasonably complete search.