Newtown, Connecticut is a town in mourning in the aftermath of the tragic shooting that took the lives of 20 children and six adults at Sandy Hook Elementary School. Many questions are being asked in the wake of the devastation, especially why the shooter did what he did. A body of research on previous mass murders may provide clues … Continue reading CNN Chief Medical Correspondent Dr. Sanjay Gupta looks inside the violent mind; researchers say none of 10 killers studied had just "snapped"