A Texas man admitted to police that he killed his family, claiming he wanted to spare them shame because he was planning a mass killing, possibly on a nearby school.
Security was heightened at schools around the eight schools of Waller, Texas, after authorities said they believed Trey Sesler was planning a Columbine-style attack.
"As a precaution, we will increase the visibility of law enforcement throughout Waller lSD. We will continue to work closely with law enforcement officials on this incident," superintendent Danny Twardowski said in a letter posted on the district's website.
Sesler, 22, was arrested Tuesday after his parents and brother were found shot to death inside of their ransacked home in Waller, which is 21 miles northwest of Houston.
Police said Sesler admitted to killing his mother Rhonda, father Lawton, and older brother, Mark.
"He further admitted to investigators that he studied serial killers to the point of grading their work and researching mass shootings in public areas that included but not limited to the Columbine shooting," Waller Police Chief Phil Rehak said at a press conference.
Police said Sesler also admitted to an array of crimes, including killing animals, setting fires and randomly shooting at businesses and schools.
Six weapons and ammunition were recovered from various homes the 22-year-old frequented, ABC affiliate KTRK reported.
Court documents obtained by the station said messages believed to be left by Sesler in his parents' home suggest he was remorseful.
"I love my mom, dad, and brother," he reportedly wrote. "Why did I do this?"
"God forgive me because I cannot forgive myself," he also wrote.
ABC News affiliate KTRK reported that authorities believe Sesler was plotting an attack on a nearby school, and he killed his family so they wouldn't have to live with the shame.
Sesler maintained a YouTube channel and was known as Mr. Anime on the video site. Several videos show Sesler playing with fake guns.
A handful of response videos were posted on the site today, as Sessler's online friends and viewers expressed shock at his arrest.
"I'm still in shock. I don't know what to think. I thought he was a cool guy," user NLMir wrote. "I feel betrayed."
Sesler has been charged with capital murder and is in Waller County Jail on $3 million bond.