 From ABC News, I'm Sherry Preston. New details are emerging about the attempted assassination of Donald Trump and how gunman Thomas Crooks got into place, allowing him to take his shots. From the Republican National Convention in Milwaukee, here's ABC's Perry Russom. Authorities now say they believe the shooter was able to access the roof by climbing over an air conditioning unit next to the building. The Secret Service director suggesting that the shape of the roof played a role.