A Korean in the US on a student visa was the shooter. Korea has universal military training, which may account for the death toll.
Interesting, as of 10:17 this morning, none of the stories use the word "immigrant" to describe him.
Google News search: Korean and gunman
Google news search: Korean AND gunman AND immigrant
Va. Tech: Gunman Student From S. Korea Associated Press, April 17, 2007
Police identified the classroom shooter as Cho Seung-Hui, 23, a senior from South Korea who was in the English department at Virginia Tech and lived in a different dorm on campus. Cho committed suicide after the attacks, and there was no indication Tuesday of any possible motive.
"He was a loner, and we're having difficulty finding information about him," school spokesman Larry Hincker said.