University City

When a bomb levels an entire block in a gentrifying Philadelphia neighborhood, killing dozens of people days before Christmas, all signs point to terrorism. But who did it? And why? Veteran Philadelphia Police Detective Frank Benson and Sergeant Ophelia Brown-Thurman are long on questions and short on answers.

Meanwhile, the high-profile racketeering trial of a crooked union official begins. It is a case in which Benson, despite his best efforts, is selected to serve on the jury-and which tu...