christi christine romans. he left no manifesto, no evidence of his motive. investigators are now discovering disturbing clues behind the shooting in las vegas. the shooter tried to buy tracer ammunition at an arizona gun show in recent weeks. >> tracer like those you see here are completely legal. they have a coating or charge that burns brightly when fired, and could have allowed fun man to target his deadly fire much more accurately. officials say the shooter bought other ammo at the gun show but could not obtain these and there are new details about the note left in the gunman's room at the mandalay bay. sheriff lombardo telling the nrk times the note contained numbers analyzed for their elements. >> it appears he was not just