BLACKSBURG, Va. — The gunman in the Virginia Tech massacre was a sullen loner who alarmed professors and classmates with his twisted, blood-drenched creative writing and left a rambling note in his dorm room raging against women and rich kids.

A chilling picture emerged Tuesday of Cho Seung-Hui – a 23-year-old senior majoring in English – a day after the bloodbath that left 33 people dead, including Cho, who killed himself as police closed in.

News reports said that he may have been taking medication for depression and that he was becoming increasingly violent and erratic.

Despite the many warning signs that came to light in the bloody aftermath, police and university officials offered no clues as to exactly what set Cho off on the deadliest shooting rampage in modern U.S. history.

“He was a loner, and we’re having difficulty finding information about him,” school spokesman Larry Hincker said.

A student who attended Virginia Tech last fall provided obscenity- and violence-laced screenplays that he said Cho wrote as part of a playwriting class they both took. One was about a fight between a stepson and his stepfather, and involved throwing of hammers and attacks with a chainsaw. Another was about students fantasizing about stalking and killing a teacher who sexually molested them.

Former classmate Ian McFarlane said that he and other students “were talking to each other with serious worry about whether he could be a school shooter.”

“When we read Cho’s plays, it was like something out of a nightmare. The plays had really twisted, macabre violence that used weapons I wouldn’t have even thought of,” former classmate Ian McFarlane, now an AOL employee, wrote in a blog posted on an AOL Web site. He said he and other students “were talking to each other with serious worry about whether he could be a school shooter.”

Associated Press writers Stephen Manning in Centreville, Va.; Matt Barakat in Richmond, Va.; Lara Jakes Jordan in Washington et al contributed to this report.