 Authorities are searching for a motive, piecing together a profile of the man they say tried to kill Donald Trump, 20-year-old Thomas Matthew Crooks. He's from Bethel Park, Pennsylvania, just south of Pittsburgh. He worked at a nursing home. Records show Crooks had no military background. The ATF traced the AR-style rifle he used to try and kill Trump, and sources told ABC News it was purchased legally by his father in 2013. ABC's Aaron Katurski in Crooks' hometown, Bethel Park, PA. ABC's Pierre Thomas.