“Finding Chandra: A True Washington Murder Mystery,” by Scott Higham and Sari Horwitz (Scribner, 304 pp) expands upon the authors’ previous coverage in The Washington Post of the Chandra Levy murder investigations. In their initial reporting, Higham and Horwitz did not join the rush of media and law enforcement implicating Congressman Gary Condit; rather, they pinpointed the true killer.