Topline The Federal Bureau of Investigation arrested a Michigan teenager Friday night for allegedly plotting a mass shooting at a synagogue, after investigators discovered messages sent by the teen on social media that praised past mass shooters and spread neo-Nazi ideology. A 19 year old was arrested for an alleged mass shooting plot. Forbes Key Facts The FBI charged 19-year-old Seann Pietila with transmitting in interstate commerce a threat to injure someone, according to a complaint filed Friday, after the agency received reports of threatening messages—including one in which Pietila said “Heil Hitler”—sent by him on Instagram, Pinterest and Discord....