In movies such as "Silence of the Lambs" and TV shows such as "Dexter," fictional serial killers who butcher scores of victims have become objects of popular fascination.
But unfortunately, serial murder isn't just something concocted by the imaginations of screenwriters and producers for our entertainment. It happens in real life.
In the U.S., victims have suffered horrible fates at the hands of serial killers such as Ted Bundy, the handsome, charismatic murder who killed more than 30 women, and Randy Kraft, a Californian who may have taken the lives 65 other men. Around the world, other killers have amassed even higher body counts, with some of them killing hundreds of people.
Why are some humans driven to kill repeatedly? In various accounts, many serial killers are depicted as people who experienced childhood traumas and sexual abuse — though that doesn't explain why others with similar experiences don't turn into violent monsters. In 2014, Psychology Today reported that the experts in FBI's Behavioral Science Unit, which studies criminal minds, believe that serial killers program themselves in childhood by engaging in an escalating series of fantasies [source: Bonn].
Here are 10 of the world's most prolific serial killers, and what we know about their motivations. As the countdown rolls on, the body count gets higher.