In October 1966, 18-year-old Cheri-Jo Bates was brutally murdered near the Riverside City College's library. Police believed the killer had disabled her car and waited for her to return, before offering her a ride. The two then spent almost half an hour in a darkened driveway before the killer attacked her with knife, severing her jugular vein and leaving her to bleed to death. Almost a month later the murderer made contact with both the police and Riverside Enterprise newspaper, sending an anonymously typed letter claiming responsibility for Bates death. Detectives believed Bates had known her killer, who might have been an ex-boyfriend or a potential suitor rejected by her, however no suspects were identified. Six months later identical notes reading "Bates had to die" were sent to the press, police and Bates father. Two of these notes contained a curious symbol at the bottom, which some believe looks similar to one used by the Zodiac Killer, who began his killing spree three years later. Just like the Zodiac, Bates's murderer has never been identified.