When Becky Watts disappeared the country was anxious for her return until police find her body. Soon stories don't add up and a computer history shows that evil lies close to home.

The case of Canadian serial killer couple Karla Homolka and Paul Bernardo.

After the death of her husband, author Helen Bailey found happiness in a new partner, but when she disappears two years later, friends and family start to ask questions.

Jennifer Pan witnessed the murder of her mother and the attempted murder of her father, but when he wakes from a coma, her father has a very different story to tell.

The FBI attempt to find a killer with no victim or geographic profile, and who covers his trail with counter forensics.

Fraternal codes are used to uncover the secrets behind a murder after a body is found.

When a criminal on probation embarks on the killing spree of ex lovers, police try to get ahead of the man who will later insist he is a victim and that society are to blame.