Inside The Criminal Mind

For decades criminologists and forensic scientists have searched for keys to unlock the twisted psyche of those who kill without remorese.

Psychologists struggle to understand the motives of criminals who kidnap victims, hold them captive and subject them to torture and rape - and at times, have children with them.

They are some of the most terrifying and tragic events of the 20th century - tales ending in horrific scenes of massacre, murder, sexual abuse and mass suicide.

Crime lords are some of the most powerful business executives on the planet, described as, "part CEO, part terrorist and part rock star.