It's an age-old question: what drives seemingly ordinary men and women to undertake the most atrocious and often bizarre crimes imaginable? There's the case of 13-year-old Daniel Morcombe, who was abducted and brutally murdered in 2003. And the notorious global manhunt for Australian Peter Scully that will see him eventually jailed for kidnapping, rape, torture and murder. These confronting cases will make you question whether some people are born evil, or born with criminal intent.