Cross by James Patterson (Alex Cross #12)

Alex has quit his job with the FBI but can't seem to stay away. When a series of brutal rapes are committed across Washington and none of the victims will talk, Sampson calls on Alex for help. Alex uses all his skills as a psychologist to persuade one of the women to tell how the attacker scared her into silence. Cross's hunt for the rapist leads him to 'the Irishman' Michael Sullivan, the deadly hitman from his past, who's returned to Washington planning to kill the new mob Don, John Maggione. How many people will meet a gruesome end while the Irishman evades the FBI, the mob hit team and Alex - still haunted by the loss of his first wife and the unsolved mystery of who killed her?