@investigationdiscovery: When detectives investigating the murder of 98-year-old Margaret Douglas in Wadsworth, Ohio, questioned a teenager, he used the word psychopath. One expert sees it as a sign he had read about the term, trying to understand why he was different and perhaps how to manage it. Watch "Signs Of A Psychopath" Tuesdays on ID and stream on @HBOMax. #SignsOfAPsychopath