Thomas Matthew Crooks, 20, from Bethel Park, Pennsylvania, attempted to assassinate former President Donald Trump at a rally. Noticed for acting suspiciously, he evaded police, took a rooftop position, and opened fire, killing one and injuring others before being fatally shot by Secret Service. The FBI is investigating the incident as domestic terrorism but hasn't found motives or clear affiliations. Crooks' troubled past included bullying and a quiet social profile, with no evident political motivations.