Warner Bros has released the initial trailer Ruben Fleischer‘s Gangster Squad. The cast for the period mob drama about the LAPD’s battle against Mickey Cohen includes Sean Penn (as Cohen), Ryan Gosling, Josh Brolin, Emma Stone, Mireille Enos, Anthony Mackie, Nick Nolte, Michael Pena, Giovanni Ribisi and others. Screenplay is by Will Beall, based on based on Paul Lieberman’s book. Pic’s release date is currently up in the air, after Warner Bros shifted calendar slots in October 2012.