'He was a loner'

Police identified the classroom shooter as 23-year-old Cho Seung-Hui (pronounced Choh Suhng-whee) of South Korea. There was no indication Tuesday of a possible motive for the attacks.

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

Cho was in the U.S. as a resident alien with a residence established in Centerville, Va., but living on campus in Harper Residence Hall, the university said.