Thomas Matthew Crooks appeared to have had multiple murders on his mind. RadarOnline.com can reveal the 20-year-old who attempted to assassinate Donald Trump at his Pennsylvania rally also researched other high-profile targets. FBI investigators accessed Crooks’ cellphone and computer and discovered he had images of both Trump and President Joe Biden on his devices. The would-be assassin had recorded the dates of the current Republican National Convention and the Democratic National Convention, scheduled to take place from Aug. 19-22 in Chicago. Crooks also spent time looking online at Attorne…