The 20-year-old man who tried to assassinate former President Donald Trump first came to law enforcement’s attention at Saturday’s rally when spectators noticed him acting strangely outside the campaign event. The tip sparked a frantic search but officers were unable to find him before he managed to get on a roof, where he opened fire. In the wake of the shooting that killed one spectator, investigators were hunting for any clues about what may have drove Thomas Matthew Crooks to carry out the shocking attack.