“It all has to come to this,” Mr. Rodger says, his voice at once placid and chilling. “Tomorrow is the day of retribution. The day I will have my retribution against humanity. Against all of you. For the last eight years of my life, ever since I hit puberty, I’ve been forced to endure an existence of loneliness, rejection and unfulfilled desires. Girls gave their affection and sex and love to other men but never to me. I’m 22 years old, and I’m still a virgin. I’ve never even kissed a girl. I have been through college for two and a half years, more than that actually, and I’m still a virgin. It has been very torturous. College is the time when everyone experiences those things such as sex and fun and pleasure. All because girls have never been attracted to me. In those years I’ve had to rot in loneliness.”

“I do not know why you girls aren’t attracted to me,” he said, “But I will punish you all for it.”

On Friday, at 9:27 p.m. in this town just north of Santa Barbara, the police said that Mr. Rodger started what turned out to be the second part of his revenge, which began shortly after he left his apartment, the first of the 12 crime scenes along Mr. Rodger’s route.

Witnesses said they saw three body bags being taken out from the apartment complex; the police said all three victims had been stabbed multiple times. Sheriff Bill Brown of Santa Barbara County described it as “a pretty horrific crime scene.”

In addition to the video, Mr. Rodger had prepared a 141-page manifesto laying out his plan for the killings, starting with luring potential victims to his apartment.

Image The gunman is believed to be Elliot Rodger, 22, who in a YouTube video said he was sexually frustrated and about to go on “a mission of retribution.”

“We have obtained and are analyzing written and videotaped evidence that suggests that this atrocity was a premeditated mass murder,” Sheriff Brown said.