BLACKSBURG, Va. (Associated Press) – The gunman suspected of carrying out the Virginia Tech massacre that left 33 people dead was identified Tuesday as a senior English major from South Korea. But police and university officials offered no clue to his motive.

“He was a loner, and we’re having difficulty finding information about him,� school spokesman Larry Hincker said, a day after the deadliest shooting rampage in modern U.S. history.

The rampage consisted of two attacks, more than two hours apart — first at a dormitory, where two people were killed, then inside a classroom building, where 31 people, including the gunman, died after being locked inside, Virginia State Police said. The gunman committed suicide.

Police identified the gunman in the classroom attack as 23-year-old Cho Seung-Hui. Cho held a green card — meaning he was a legal, permanent U.S. resident — and had been in the United States since 1992, federal officials said.

He was living on campus, in a different dorm from the one where the bloodbath began, the university said.

One law enforcement official said Cho̢۪s backpack contained a receipt for a March purchase of a Glock 9 mm pistol. As a permanent legal resident of the United States, Cho was eligible to buy a handgun unless he had been convicted of a felony.

Investigators stopped short of saying Cho carried out both attacks. But ballistics tests show one gun was used in both, Virginia State Police said.

And two law enforcement officials, speaking on condition of anonymity because the information had not been announced, said Cho̢۪s fingerprints were found on the two guns used in the rampage. The serial numbers on the two weapons had been filed off, the officials said.

Col. Steve Flaherty, superintendent of the Virginia State Police, said it was reasonable to assume that Cho was the shooter in both attacks but that the link was not yet definitive. “There’s no evidence of any accomplice at either event, but we’re exploring the possibility,� he said.

South Korea’s Foreign Ministry expressed its condolences, and said South Korea hoped that the tragedy would not “stir up racial prejudice or confrontation.�

A memorial service was held for the victims Tuesday afternoon at the university, and President Bush attended, the White House said. Gov. Tim Kaine was flying back to Virginia from Tokyo for the gathering.

Classes were canceled for the rest of the week.

Many students were leaving town quickly, lugging pillows, sleeping bags and backpacks down the sidewalks.

Will Nachlas, 19, a freshman from Hershey, Pa., sat on a bench, waiting for a ride.

“The majority of people are leaving campus, trying to get away,� he said. “Lots of people are going home, and lots of people’s parents took them home. They don’t even know when they’ll come back.�

The first deadly attack was at the dormitory around 7:15 a.m., but some students said they didn̢۪t get their first warning about a danger on campus until two hours later, in an e-mail at 9:26 a.m. By then the second attack had begun.

Two students told NBC’s “Today� show they were unaware of the dorm shooting when they walked into Norris Hall for a German class where the gunman later opened fire.

The victims in Norris Hall were found in four different classrooms and a stairwell, Flaherty said. Cho was found dead in one of those classrooms, he said.

Derek O’Dell, his arm in a cast after being shot, described a shooter who fired away in “eerily silence� with “no specific target — just taking out anybody he could.�

After the gunman left the room, students could hear him shooting other people down the hall. O’Dell said he and other students barricaded the door so the shooter couldn’t get back in — though he later tried.

“After he couldn’t get the door open he tried shooting it open … but the gunshots were blunted by the door,â€? O’Dell said.

University President Charles Steger emphasized that the university closed off the dorm after the first attack and decided to rely on e-mail and other electronic means to spread the word.

He said that before the e-mail was sent, the university began telephoning resident advisers in the dorms and sent people to knock on doors. Students were warned to stay inside and away from the windows.

“We can only make decisions based on the information you had at the time. You don’t have hours to reflect on it,� Steger said.