The Santa Barbara County Sheriff's department said Sunday that they were unaware of the disturbing videos Elliot Rodger posted online before going on a killing spree Friday.

In videos posted as recently as the day of the killings, Rodger ranted about hating minorities and women, and "slaughtering" those who have wronged him. Rodger killed six people and injured 13 others before committing suicide on Friday evening.

The Santa Barbara City College student posted at least 22 videos to YouTube, but many were removed due to content violations. The videos were reposted last week, and Rodger's mother, Li Chin, discovered at least one of them on Friday.

The mother was also made aware of a disturbing email received by her son's therapist the same evening. Li Chin contacted her ex-husband, Hollywood director Peter Rodger, and the two drove to Isla Vista, near the University of California Santa Barbara campus, where their son lived.

The school's students were a source of ire for the 22-year-old, who rants on YouTube, a bodybuilding blog, and in a 141-page manifesto about his contempt for sorority girls and other women who would not have sex with him. Rodger was angry that he was still a virgin, and viewed the men that women chose over him as his enemies.

While Li Chin and Peter drove on the highway, they heard news of the killings over the car radio.

Rodger stabbed three men to death in his apartment: Cheng Yuan Hong, 20, George Chen, 19, and Weihan Wang, 20. He then drove his BMW 328i to the UC Santa Barbara campus and killed Delta Delta Delta sorority sisters Katherine Cooper, 22, and Veronika Weiss, 19. Christopher Michael-Martinez, 20, was killed seemingly at random at a local deli.

After running over bicyclists and pedestrians with his car and engaging in shoot-outs with Santa Barbara police, Rodger shot himself in the head inside his vehicle.