Kemper worked a series of odd jobs before securing work with the State of California's Department of Public Works/Division of Highways in District 4 (now known as Department of Transportation or Caltrans). By that time, his height had reached 6 feet, 9 inches, and he weighed more than 300 pounds (136 kg). Between May 1972 and February 1973, Kemper embarked on a spree of murders, picking up female students hitchhiking, taking them to isolated rural areas and killing them. He would stab, shoot or smother the victims and afterwards take the bodies back to his apartment where he would have sex with them and then dissect them. He would often dump the bodies in ravines or bury them in fields, although on one occasion he buried the severed head of a 15-year-old girl in his mother's garden as a kind of sick joke, later remarking that his mother "always wanted people to look up to her." He killed six college girls (including two students from UC Santa Cruz, where his mother worked, and one from Cabrillo College). He would often go hunting for victims after arguing with his mother.
In April 1973, Kemper battered his mother to death with a pick hammer while she slept. He decapitated her, raped her headless body and used her head as a dartboard, after putting her vocal cords in the garbage disposal, but the machine could not break the tough tissue down and regurgitated it back into the sink. "That seemed appropriate," Ed said after his arrest, "as much as she'd bitched and screamed and yelled at me over so many years." His murderous urges not yet satiated, he then invited his mother's best friend over and killed her too, by strangulation. He then drove eastward, but when no word of his crimes hit the radio airwaves he became discouraged, stopped the car, called the police and confessed to being the Co-ed Killer. He told them what he had done and waited for them to pick him up, seemingly unashamed as he confessed to necrophilia and cannibalism. At his trial he pleaded insanity, but he was found guilty of eight counts of murder. He asked for the death penalty, but with capital punishment suspended at that time, he instead received life imprisonment.
