His parents moved to Centreville, Va., about 20 miles west of the capital, and reportedly ran a dry cleaning business in the fast-growing suburb that has drawn many South Korean immigrants.
Cho attended Westfield High School and was a member of the science club, school officials said. He graduated in 2003.
Virginia state police teams searched the family home for evidence late Monday night. The family lived in an off-white, two-story town house in a cul-de-sac of middle-class homes. The home was deserted Tuesday.
Cho's first name, in capital letters, was still posted Tuesday on an orange tag taped next to the door to his dorm room, No. 2121. The living room featured a burgundy sofa, a small coffee table and an array of empty water bottles and soda cans.
His roommates said they had not noticed any weapons or unusual items -- except Monday morning, after Cho left for class, when Aust saw a screwdriver on his roommate's desk.
Other times, Aust found Cho sitting silently in a desk chair, apparently oblivious. "He'd just kind of be staring at his desk, just staring at nothing," he said. "I would pass it off like he was just weird."
Several students and professors who had seen Cho's poetry, plays and fiction from 2005 described it as filled with graphic violence.
Lucinda Roy, chairwoman of the English department, worried about his stability and urged him to seek counseling at the school. He apparently did not.
Giovanni, the former creative writing instructor, said she took some of Cho's writing to Roy and told her that she could no longer teach him.
"I couldn't allow him to destroy my class," she said.
Roy agreed to teach Cho in a private tutorial setting, Giovanni said.
Roy gave Cho an A for the semester. Giovanni thinks he got the grade not for talent or effort, but because he was "intimidating" -- and that it was decided it was best to keep him happy.
"I think he liked the idea that he was a scary guy," Giovanni said. "Some people like that. That's how they define themselves."
Stephanie Derry, a senior English major, took a playwriting class with Cho this spring, according to the campus newspaper, Collegiate Times. Cho barely spoke to the other students, she said.
"His writing, the plays, were really morbid and grotesque," Derry told the paper. "His kind of writing was pretty peculiar, but when we asked him if he had any comments after we'd reviewed his work, he would just shrug and say nothing."
