DOYLESTOWN, Pa. (AP) — A Pennsylvania prosecutor says the man accused of shooting and decapitating his father in their home northeast of Philadelphia and posting a video of the severed head purchased a gun the previous day. Bucks County District Attorney Jennifer Schorn said Friday that 32-year-old Justin D. Mohn was “acting with clear mind” when he allegedly killed his father, Michael F. Mohn, at their home in Levittown on Tuesday. Mohn’s mother discovered her husband’s body. Justin Mohn faces charges of first-degree murder, abusing a corpse and possession of instruments of crime. The public defenders representing him are declining comment.