The film, a mob thriller set in Los Angeles during the 1940s and '50s, starring Sean Penn and Ryan Gosling, will reach theaters on January 11, 2013, rather than its originally scheduled September 7 debut, a Warner Bros. spokeswoman said on Thursday.

The studio is considering whether to edit or delete the scene in which mobsters burst through a movie screen while opening fire on a theater audience, a person familiar with the studio's plans told Reuters.

The Warner Bros. spokeswoman declined to comment on whether the movie will be changed.

The studio acted after a lone gunman shot and killed 12 people on July 20 during a midnight showing of Batman movie "The Dark Knight Rises," another Warner Bros. release.

Just after the incident, Warner Bros. pulled "Gangster Squad" promotional trailers that featured the shooting scene and were running ahead of "Dark Knight Rises" in some theaters.

Warner Bros. is owned by Time Warner Inc.

(Reporting By Lisa Richwine; editing by Bob Tourtellotte and Andre Grenon)

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