Shooter, Cho, 'Was a Loner,' Official Says

Cho Seung-hui, 23, the Virginia Tech student who police believe is responsible for killing 33 people yesterday, was "a loner, and we're having difficulty finding information about him," said university spokesman Larry Hincker.

Law enforcement officials have provided this official photo of Cho Seung-hui, the man they identify...

Law enforcement officials have provided this official photo of Cho Seung-hui, the man they identify as the killer at Virginia Tech. Cho was a 23-year-old student of Korean descent who lived on campus. Sources tell ABC News he was carrying a backpack with a receipt for the purchase of a 9 mm handgun.

Police identified Cho, a native of South Korea and resident alien who lived in Centreville, Va., as the shooter by linking the fingerprints at the scene to his immigration documents.

Police say the senior English major, who lived in Harper Hall dormitory on the university campus, was likely responsible for both shootings at the university, the first of which took place at around 7:15 a.m. Monday morning when two people were killed at West Ambler Johnston Hall dormitory. Later that morning, the remaining victims were killed in Norris Hall, the engineering studies building.

ABC News has learned that Cho left behind a note after the killings at West Ambler Johnston Hall. He then returned to his own room, rearmed and entered Norris Hall, roughly a half a mile away, to continue his shooting rampage.

Cho came to the United States with his family in 1992 at age 8 and first settled in Detroit, according to State Department officials. He last renewed his green card in 2003.

According to the Washington Post, his parents live in Fairfax County, Va., an affluent Washington suburb, just outside of Alexandria, Va. He is a graduate of Westfield High School in Fairfax.

Legal permanent resident aliens may purchase firearms in the state of Virginia. A resident alien must, however, provide additional identification to prove he or she is a resident of the state.