According to a report from NBC News, the roof from which 20-year-old Thomas Matthew Crooks shot Donald Trump was identified by the Secret Service as a potential security concern before the assassination attempt.
Crooks climbed onto the roof of a glass testing company building 500 feet from where Trump was speaking at a podium in Butler, Pennsylvania. A source told NBC News:
There should have been someone on the roof or securing the building so no one could get onto the roof.”
According to the report, the Secret Service had indicated that the building would fall under the jurisdiction of local police because it was outside the grounds of the meeting.