 With former President Trump back campaigning at a rally in Grand Rapids, Michigan, there's an update on the assassination attempt a week ago at a Pennsylvania rally and the gunman Thomas Crooks from ABC's J. O'Brien. Authorities now investigating whether Crooks used a drone to survey the rally location prior to the shooting. A comprehensive timeline reviewed by ABC News found law enforcement first spotted the shooter at least an hour before he opened fire. ABC's J. O'Brien and Grand Rapids.