A murderer’s row of leading men — Sean Penn, Ryan Gosling and Josh Brolin — are in talks to star in Warner Bros.’ “Gangster Squad.”

Warner offered the roles to Penn and Gosling after greenlighting the pic, but negotiations did not begin until now.

Ruben Fleischer is helming from a script by Will Beall. Dan Lin and Kevin McCormick produce through Lin Pictures and Langley Park.

Pic is based on the Los Angeles Times’ seven-part series “Tales From the Gangster Squad,” to which Warner acquired the rights two years ago.

The articles, penned by Paul Lieb­erman, chronicled efforts by the Los Angeles Police Dept. to deal with increasing crime and corruption in 1940s L.A. by forming what was dubbed the Gangster Squad in an effort to keep East Coast organized crime figures from planting roots in the city.

Sources tell Variety that Penn has gone back and forth on whether to do the film and at one point had passed on the project.

Warners countered with a new offer that Penn agreed to; that led the studio to move forward with negotiations on other roles.

Penn had also been considering the Warner Bros./Dark Castle co-production “The Last Photograph” with Christian Bale.

Gosling will next be seen in “Crazy Stupid Love” for Warner Bros.

Brolin is currently shooting “Men in Black III” for Sony and was most recently seen in Paramount’s “True Grit.”

Penn is repped by CAA and Hirsch Wallerstein Hayum Matlof and Fishman.

Brolin is repped by CAA.

Gosling is repped by IFA Talent Agency, Artist Management and Sloane Offer Weber & Dern.