The Virginia Tech Massacre was the worst shooting in US history at the time, only being surpassed by the Orlando Nightclub shooting in 2016.

39 members of Heaven's Gate took their lives in 1997 believing it would help them survive an oncoming apocalypse.

Charles Cullen worked at numerous hospitals in the New Jersey area while his killing spree went largely unnoticed.

A lot of myths and misinformation about the perpetrators has circulated since the school shooting in 1999.

Human rights activist Malcom X was assassinated in 1965, but speculation about the identity of his killers has persisted for decades.

Few people on the planet have experienced the psychology of murder quite as intensely as Lt. Joe Kenda has

A decade has passed since that fateful road trip and Timmothy still remains missing | Image: Shutterstock