Law enforcement sources told ABC News that shortly before alleged gunman Payton Gendron's high school graduation, he allegedly wrote a paper that referenced committing murder-suicide. WATCH FULL EPISODES OF WORLD NEWS TONIGHT: https://abc.com/shows/world-news-tonight WATCH WORLD NEWS TONIGHT ON HULU: https://bit.ly/3iQLwPp #Buffalo #Shooting #SuspectBackground #WorldNewsTonight