BLACKSBURG, Va. — The gunman suspected of carrying out the Virginia Tech massacre that left 33 people dead was described Tuesday as a sullen loner whose creative writing in English class was so disturbing that he was referred to the school's counseling service.

News reports also said that he may have been taking medication for depression, that he was becoming increasingly violent and erratic, and that he left a note in his dorm in which he railed against "rich kids," "debauchery" and "deceitful charlatans" on campus.

Cho Seung-Hui, a 23-year-old senior majoring in English, arrived in the United States as boy from South Korea in 1992 and was raised in suburban Washington, D.C., officials said. He was living on campus in a different dorm from the one where Monday's bloodbath began.

Police and university officials offered no clues as to exactly what set him 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.

On Tuesday afternoon, thousands of people gathered in the basketball arena, and when it filled up, thousands more filed into the football stadium, for a memorial service for the victims. President Bush and the first lady attended.

Virginia Tech President Charles Steger received a 30-second standing ovation, despite bitter complaints from parents and students that the university should have locked down the campus immediately after the first burst of gunfire. Steger expressed hope that "we will awaken from this horrible nightmare."

"As you draw closer to your families in the coming days, I ask you to reach out to those who ache for sons and daughters who are never coming home," Bush said.