Trey Sesler was originally a YouTube reviewer, largely discussing anime, guns, and video games. However, as time went on, he started showing signs that his sanity was slipping: such signs included obsessive research of serial killers, killing animals, using real guns in his videos, doing videos about his guns, and shooting buildings in the middle of the night.
“Mr. Anime is planning something” was one of his last videos on his Channel in which he talked about rewarding himself with a 3 week break from Youtube.
After these 3 weeks, instead of returning to Youtube, Trey shot and killed both his parents and his 26-year-old brother Mark with a high-powered rifle. After commiting the act, he wrote down on the walls "Why did I do this? I love my mom, dad and brother.“
After a one day manhunt Trey was arrested. During interrogation he revealed that he had actually killed his family to spare them from knowing what he planned on doing next: He had become so obsessed with killings and weapons (especially everything Columbine related) that he ultimately wanted to shoot up the Waller Junior High School, and his goal was to kill at least 70 people. Although, he was caught before he could accomplish this.
A large number of the anime he reviews have violent themes. For example, in one, which is called Highschool Of The Dead, Sesler has a large rifle in his hands while he talks to the camera. At one point he seems to get very excited when talking about the zombies killing the mortals as there is ‘blood everywhere’. Yet another one is called Death Note and another one is called Slayers. The beginning of all of his reviews, he plays a short clip in which he shoots someone in the chest. His Channel is still online.