Who is Edmund Kemper from Whoever Fights Monsters and what is their importance?

Ressler uses Edmund Kemper as an example of a mixed type of serial killer. He was large man, six foot nine, who started his murder spree by killing his grandparents, after which, he went on to kill several other women around Santa Cruz. Kemper eventually killed his mother and used her head as a dartboard. He also killed his mother's best friend.