In 1924, two Chicago rich kids killed for kicks, for the intellectual challenge posed by 'the perfect crime'.
Psychopath Peter Manuel is Scotland's most notorious serial killer, murdering at least eight people in Glasgow in the 1950s.
Mary Bell was only 11-years-old when she killed 4-year-old Martin Brown and 3-year-old Brian Howe.
John Straffen became the UK's longest serving prisoner after he murdered three little girls in the 1950s.
Any one of ten traits can indicate someone is a serial killer. Edmund Kemper has them all.