Later that day it was discovered that Castillo had killed his father to "put him out of his misery." He also made the statement "Columbine, remember Columbine," while entering a patrol car, referring to the attack at Columbine High School in Colorado in 1999. He sent a written letter and videotape to the "Chapel Hill News" prior to the shooting, that made reference to school shootings. He also sent an e-mail to the principal of Columbine High School saying "Dear Principal, In a few hours you will probably hear about a school shooting in North Carolina. I am responsible for it. I remember Columbine. It is time the world remembered it. I am sorry. Goodbye."