Virginia Tech killer’s letter explains his motive

In the hours between his two attacks at Virginia Tech, gunman Cho Seung-hui sent a chilling video to a U.S. TV network, NBC News. Cho sent photographs of himself, a lengthy letter and video footage showing his anger and hatred.

The Korean student portrays himself to be a defender of the weak and expresses disgust at what he calls the hedonism around him.

Police say Cho was committed to a mental health unit in 2005. There had previously been complaints of Cho stalking two female students and claims he'd shown signs of being suicidal. Cho's professors had been concerned about his writing containing violent scenes.

Cho Seung-hui killed 32 people in a rampage across the Virginia Tech campus on Monday.