The police identified Cho Seung-Hui, a 23-year-old student, as the killer of 32 people in the shooting rampage at the Virginia Polytechnic Institute, releasing new information on Tuesday about the troubled mind of a young man few people on campus knew.
Federal investigators said Cho — a South Korean immigrant who Americanized his name and preferred to be known as Seung Cho — left behind a note that they described as a lengthy, rambling and bitter list of complaints focusing on moral laxity and double-dealing he found among what he viewed as wealthier and more privileged students on campus.
And new information emerged that may help explain a fateful two-hour delay by university officials in warning the campus of a gunman at large. According to search warrants and statements from the police, campus investigators had been busy pursuing what appears to have been a fruitless lead in the first of two shooting episodes Monday.
After two people, Emily Jane Hilscher, a freshman, and Ryan Clark, the resident adviser whose room was nearby in the dormitory, were shot dead, the campus police began searching for Karl D. Thornhill, who was described in Internet memorials as Hilscher's boyfriend.
According to a search warrant filed by the police, Hilscher's roommate had told the police that Thornhill, a student at nearby Radford University, had guns at his town house. The roommate told the police that she had recently been at a shooting range with Thornhill, the affidavit said, leading the police to believe he may have been the gunman.
But as they were questioning Thornhill, reports of widespread shooting at Norris Hall came in, making it clear that they had not contained the threat on campus. Thornhill was not arrested, although he continues to be an important witness in the case, the police said.
At the time of the dormitory shootings, Col. W. Steven Flaherty, the superintendent of the Virginia State Police, said, "There was certainly no evidence or no reason to think that there was anyone else at that particular point in time."
State officials continued to defend the actions of the campus authorities. John W. Marshall, the Virginia secretary of public safety, said Charles W. Steger, the president of Virginia Tech, and Chief Wendell Flinchum of the campus police "made the right decisions based on the best information that they had available at the time."
At an afternoon news briefing, Gov. Timothy M. Kaine said Steger had asked him to appoint a committee to examine the university's response and try to answer some of the remaining questions about the gunman's actions.
After the shootings, the state police executed another search warrant, this time for Cho's dormitory room. The warrant said a bomb threat against the engineering school buildings was found near Cho's body. The warrant mentioned two other bomb threat notes against the campus received over the past three weeks.
Cho had used two handguns, a 9-millimeter and a .22-caliber, to shoot dozens of rounds, leaving even those who survived with multiple bullet wounds, officials said. The guns were bought legally in March and April. Flaherty said that although one of those guns had been used in the dormitory shooting, investigators were not ready to conclude that the same gunman was responsible for both episodes. But he said there was no evidence of another gunman or an accomplice.
Among the central unknowns is what prompted the gunman to move to Norris Hall, which contains engineering and other classrooms, where all but the first two killings took place. The authorities said Cho's preparations, including chaining the doors, suggested planning and premeditation, rather than a spontaneous event.
Bodies were found in four classrooms and the stairwell of the building, Flaherty said.
"You all have reported that this is the most horrific incident that's occurred on a college campus in our country, and the scene certainly bore that out," he said. "Personal effects were strewn about the entire second floor at Norris Hall. So it made it much more difficult for us to identify students and faculty members that were victims."
Officers also found several knives on Cho's body. They first identified him by a driver's license found in a backpack near the scene of the shootings, although it was not clear at first whether the backpack belonged to the gunman. But the name was checked against a visa application, and when a fingerprint on one of the weapons matched a print on the visa application, the authorities made a positive identification. The print matched another print left in the first shooting location.
Prescription medications said to be related to treatment of psychological problems were found among Cho's effects, but officials did not specify what drugs they were.
In addition, investigators were reviewing recent bomb threats at the university in an effort to determine whether the gunman might have been involved in them, as an effort to test the university's emergency response procedures.
Lucinda Roy, an English professor, said Cho's writing, laced with anger, profanity and violence, concerned several faculty members. In 2005, she sent examples to the campus police, the campus counseling service and other officials. All were worried, but little could be done, she said.
Roy said she would offer to go with Cho to counseling, just to talk. "But he wouldn't say yes, and unfortunately I couldn't force him to do it," she said. Students were also alarmed that Cho was taking inappropriate pictures of women under desks, she said.
In all, 33 people died Monday, including Mr. Cho and at least four faculty members. The victims' names were not officially released, but most appeared to be in their late teens or early 20s. They included Liviu Librescu, a Holocaust survivor, and Reema Samaha, a freshman and a devoted dancer. Hilscher wanted to be a veterinarian; Clark was a member of the marching band. "This is a grief that does not know an international boundary," Kaine said.
By Tuesday afternoon there were still 14 injured victims at four hospitals, out of 28 initially transported from the scene, two of whom died. The 14 included two at a Level 1 trauma center in Roanoke, one in critical condition and the other in serious condition.
One of the luckier ones was Kevin Sterne, a senior who will graduate in a few weeks. He was hit twice in the right thigh, piercing an artery.
Sterne grabbed an electrical cord and fashioned a tourniquet until help arrived. "I think there's a good chance he would have died," said Dr. David B. Stoeckle of Montgomery Regional Hospital in Blacksburg.
Classes at Virginia Tech were canceled for the rest of the week, and Steger announced that Norris Hall would remain closed for the rest of the semester.
Thousands of students and faculty and staff members gathered Tuesday afternoon at Cassell Coliseum, the university's basketball arena, for a solemn convocation. President Bush and Laura Bush attended the gathering and then spent much of the afternoon consoling members of the university family.
"This is a day of mourning for Virginia Tech, and it is a day of sadness for our entire nation," Bush said in his remarks.
The president said that Monday began like any other school day, but then took a dark turn.
"By the end of the morning," he said, "it was the worst day of violence on a college campus in American history — and for many of you here today, it was the worst day of your lives."