 Federal investigators are working to determine a motive behind the attempted assassination of Donald Trump last weekend. NPR's Quill Lawrence has the latest from western Pennsylvania. Residents of this quiet Pittsburgh suburb are still struggling to explain how Thomas Crooks, a young man with good career prospects and no past signs of trouble, has made their town notorious. It's been a great place to grow up and a great place to see a lot more young families in recent years come and move in.