Law enforcement sharpshooters position themselves on a roof prior to a rally by Republican presidential nominee, former U.S. President Donald Trump, at the Butler Farm Show Inc. on October 05 ...

Thomas Matthew Crooks flew a drone over Trump's rally site hours before his assassination attempt. Crooks reportedly used a DJI-made camera drone to survey the area.

Trump is returning to Butler, Pennsylvania for the first time since his last rally there where an assassination attempt took place. (Photo by Anna Moneymaker/Getty Images) ...