An eight-month investigation into the deadly rampage in Isla Vista, California, closed on Thursday, concluding that Elliot Rodger acted alone and that better systems are needed for identifying troubled individuals who might be capable of killing others.
The investigation also found disturbing searches in Rodger's Internet history and other online activities.
The 64-page report (here) conducted by the Santa Barbara County Sheriff's Office provides a detailed look at both at Rodger's "premeditated, murderous rampage" as well as an analysis of the evidence uncovered after Rodger killed himself.
In May 2014, 22-year-old Rodger stabbed three men to death inside his apartment, then went on a shooting rampage that began at UC Santa Barbara's Alpha Phi sorority house, when he fired on students from his car. He went on to fire rounds at multiple locations in the small town, killing another student at a nearby deli and wounding others.
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He killed himself at the end of the rampage.
One focus of the report was whether Rodger acted alone.
"The convoluted nature of this rapidly unfolding massacre, and the nature in which it quickly ended, initially led law enforcement to believe that there were two suspects," Detective Joe Schmidt said in the report.
But detectives found no evidence to show he was assisted in any way.
At the time of the killings, Rodger was seeing a life coach who had become worried about his behavior. Deputies had been dispatched to his apartment for a welfare check by his mother on April 30, as she was worried about disturbing videos he had posted on YouTube.
He had been treated for mental health issues for many years, according to the report. He had also come into contact with deputies in the months before the shooting after an altercation with his roommate and others.
The report indicates, consistent with previous reports, that deputies did not find Rodger to be a danger to himself or others. They did not find that they had enough reason to place him on a mental health hold.
Rodger emailed a manifesto to some family members just minutes before he went on the shooting rampage, but hours after the first three stabbings, saying he was driven to kill women because no woman had wanted to date him, saying "Women’s rejection of me is a declaration of war."
The manifesto referenced slicing throats, bludgeoning, slashing and using his apartment as a torture chamber.
After Rodger killed himself, detectives also found in Rodger's Internet history that he had done extensive research into Nazis in the report, including searches on his laptop including the phrase "Did Adolf Hitler have a girlfriend."
They discovered Rodger had a strong interest in violent video games, movies and books.
He also uploaded a disturbing video to YouTube detailing his complaints against a society he felt had rejected him.
While the investigation concluded that numerous mental health professionals had not been able to foresee his violent crime spree, it encouraged a development of new tactics and methods of sharing information that might help prevent another person with known mental health issues from being able to carry out such a rampage again.
"It is hoped that a thorough review of these materials by both law enforcement and mental health professionals will lead to the development of some new techniques and practices in identifying and treating such troubled persons."