A look at Rodger’s browser history revealed he was interested in Hitler, Nazis and the practices of the "Third Reich." One search included the phrase, “Did Adolf Hitler have a girlfriend."
The investigation also found that the suspect researched ways to “silently kill” with a knife before stabbing his victims. Several pillows on his bed had stab marks in them suggesting Rodger had practiced stabbing his victims before his attacks.
The investigation also found that Rodger had an interest in violent videogames, movies and books.
Clips on Rodger’s phone showed that he had been eavesdropping on his housemates’ and neighbors’ conversations.
Toxicology tests determined Rodger had caffeine and two psycho-active drugs in his system during the time of his death, and that the suspect acted alone.