On March 20, 2012, Trey Eric Sesler, a 22-year-old former YouTuber known online as "Mr. Anime," shot and killed his mother, father, and older brother in the family's home in Waller, Texas. Police had responded to a report of gunshots at the home the previous day but found nothing at the time. According to accounts of the killings, Sesler's mother, Rhonda Sesler, took him to the garage to show him a dent in her car, and he shot her at point-blank range with a .22 rifle. He then shot his brother, Mark Sesler, who initially survived and locked himself in a bathroom before Sesler broke down the door and fatally shot him again. His father, Lawton Sesler, was then shot after being awakened by the gunfire. Sesler moved through the home with an AR-15-style rifle, firing additional shots at his mother and delivering final shots to his brother and father. He wrote messages on the walls of the home, including expressions of love for his family and requests for forgiveness, and killed the family's pets.
Investigators said Sesler had planned to carry out a school shooting at Waller High School, from which he had graduated, after killing his family. He loaded a Hi-Point model 995 carbine rifle and more than 100 rounds of ammunition into his car and drove to the school, where he sat in the parking lot before deciding not to proceed, later telling investigators the plan had become "too real." He instead drove to a friend's home in Magnolia, Texas, where he spent the night. Police discovered the bodies of Sesler's family at approximately 1 p.m. on March 20, 2012, after relatives requested a welfare check, and an arrest warrant was issued. Sesler was arrested at the friend's house that evening.
Investigators stated Sesler was heavily influenced by mass murder events, including the Columbine High School massacre, and had researched notorious killers such as Ted Bundy, David Berkowitz, and Jeffrey Dahmer. He had no prior criminal record but admitted to investigators that he had previously killed animals and fired weapons near schools at night. Waller police chief Phil Rehak described the crime scene as a "war zone."
Sesler was charged with three counts of capital murder. On August 2, 2012, he pleaded guilty to all charges and was sentenced to life imprisonment without the possibility of parole. He reportedly told the judge to forgo any appeal rights out of fear he remained a danger to himself and others. Some Waller residents had anticipated a death sentence and expressed disappointment with the outcome. As of 2024, Sesler was reported to be incarcerated at the Terrell Unit in Brazoria County, Texas, having previously been held at the McConnell Unit in Bee County, Texas.