Public Enemies is a 2009 American biographical mob drama film directed by Michael Mann and written by Mann, Ronan Bennett and Ann Biderman. Based on author Bryan Burrough's ambitious tome Public Enemies: America's Greatest Crime Wave and the Birth of the FBI, 1933-43, director Michael Mann's sprawling historical crime drama follows the efforts of top FBI agent Melvin Purvis (Christian Bale ) in capturing notorious bank robber.