As of Monday evening, only one of the Virginia Tech victims had been officially identified. Police officials said they were not yet ready to identify the gunman or even say whether one person was behind both attacks, which wreaked devastation on this campus of 36,000 students, faculty members and staff.Federal law enforcement officials in Washington said the gunman might have been a young Asian man who recently arrived in the United States. A university spokeswoman, Jenn Lazenby, could not confirm that report but said the university was looking into whether two bomb threats at the campus, — one last Friday, the other earlier this month — might be related to the shootings.

The university’s president, Charles W. Steger, expressed his “horror and disbelief and sorrow” at what he described as a tragedy of monumental proportions. But questions were immediately raised about whether university officials had responded adequately to the shootings. There was a two-hour gap between the first shootings, when two people were killed, and the second, when a gunman stalked through the halls of an engineering building across campus, shooting at professors and students in classrooms and hallways, firing dozens of rounds and killing 30. Officials said he then shot himself so badly in the face that he could not be identified. The university did not send a campus wide alert until the second attack had begun, even though the gunman in the first had not been apprehended.

The Virginia Tech police chief, Wendell Flinchum, defended the university’s decision to keep the campus open after the first shootings, saying the information at the time indicated that it was an isolated event and that the attacker had left campus. At an evening news conference, Chief Flinchum would not say that the same gunman was responsible for the shootings in the dormitory and the classrooms. He said he was awaiting ballistics tests and other laboratory results until declaring that the same person carried out both attacks.He said accounts from students at the dorm had led the police to a “person of interest” who knew one or both of the victims there. The police were interviewing him off campus at the time of the shootings at Norris Hall. Chief Flinchum said officers had not arrested the man.