 This is Jim Ryan in Milwaukee. Even inside the secure confines of the convention venue, Donald Trump was flanked by Secret Service agents. We now know that 20 minutes passed between the time that sharpshooters spotted gunman Thomas Matthew Crooks and the moment that Crooks opened fire on Trump last Saturday in Butler, Pennsylvania. Officials investigating the assassination attempt told lawmakers in an unclassified briefing that they still haven't established a firm motive for Crooks' actions. Jim Ryan, ABC News, Milwaukee.