Police pored over the writings of a student who massacred 32 people at Virginia Tech University as they searched on Wednesday for further clues to why he went on the worst shooting rampage in modern US history.
A chilling portrait of Cho Seung-Hui, a 23-year-old South Korean, has emerged from accounts of fellow students and teachers and from writings for his English degree that were dominated by disillusioned, violent characters.
"I felt he was a very lonely, isolated kind of person the whole time," Lucinda Roy, an English professor who taught Cho, told CNN on Tuesday.
"He would always wear sunglasses even inside, and a cap."
As students and teachers grieved, police said they were examining Cho's "considerable" writings for clues about what may have sparked Monday's rampage on the rural campus.
The Washington Post and other media quoted police sources as saying Cho left a note attacking what he called rich, spoiled students. Police said there was no suicide note.
Cho, who immigrated to the United States 15 years ago and was raised in suburban Washington, DC, killed himself on Monday after opening fire in classrooms in a building where he apparently chained doors to prevent escape before cutting down 30 victims one by one.
He was found with the words "Ismael Ax" written in red ink on one of his arms, the Post reported law enforcement sources as saying.
It was unclear what the words meant. Cho used two handguns, which police confirmed he had purchased legally, and stopped only to reload.
Police have stopped short of saying he was responsible for the shooting deaths of two other people two hours earlier at a dormitory but said tests showed the same gun was used in both incidents.
Investigation of response
With many students still angry about the university's failure to shut down the campus after the first shooting, Virginia Gov Tim Kaine was working to appoint a team of independent officials to examine the response.
Neighbors, roommates and teachers described Cho as a withdrawn person who rarely talked to anyone. Two students who said they were Cho's roommates said he had harassed several female students and once told them he wanted to kill himself, which prompted the roommates to report concerns about him to the police.
The massacre has revived the debate over US gun control laws, which are the most lenient in the Western world. But it appeared unlikely the shooting would lead to stricter laws or have much impact on the 2008 presidential race because most leading candidates already favor gun controls and are unlikely to gain by pushing the issue.
ABC News reported that one of the guns, a 9mm Glock, and ammunition were purchased on March 13 for $571 from a gun shop about 30 miles from the Virginia Tech campus.
President George W Bush, in an interview on NBC on Tuesday, refused to answer questions on the gun control issue.
"Now is not the time," he said. "I'm more interested in helping people heal right now. And that's why we're here."