An Alabama teenager charged with murdering five members of his family had attempted to poison his stepmother before the 2019 slayings, according to court documents released Thursday. Prosecutors said Mason Sisk, who was 14 when his father, stepmother, and three young siblings were found fatally shot in their Elkmont home, had a history of acting aggressively toward his family. In the most extreme example, prosecutors described how Sisk allegedly put peanut butter in his stepmother’s coffee “when he was aware that she had a severe peanut butter allergy.” To his siblings—a 6-year-old boy, a 5-year-old girl, and a 6-month-old boy—Sisk was also “forceful,” often displaying “‘anger control’ issues,” according to the filing. He is being tried as an adult and has pleaded not guilty to multiple charges of capital murder.