Early in the morning on 16th April 2007, on the Virginia Tech campus in America, a 23-year-old student called Seung-Hui Cho killed 32 people before turning his gun on himself. The incident became the biggest mass shooting in peacetime US history.

Using extensive access to key witnesses, Massacre at Virginia Tech delves into the mystery of how Cho, a young man with no criminal history, became a mass murderer.

Cho suffered from mental health problems. So do one in five Americans, but very few become killers. Who was this deranged young man and what caused him to plan and carry out this tragic event?