A deranged art teacher allegedly filmed himself stabbing three people — killing one of them — just hours after he had been giving out Halloween candy to trick-or-treaters, according to authorities Matthew Regnier, a 33-year-old instructor at Monument Academy in El Paso County, Colorado was found “fully naked and bloodied” and holding a 2-year-old child when police responded to a domestic dispute call at a home in Colorado Springs on Friday night. The young child was “present, watching and