On May 24, 2012, it was announced that Warner Bros. (WB) had acquired the rights to the book with Bradley Cooper set to produce and star in the screen adaptation. Cooper had thought of Chris Pratt to play Kyle, but WB agreed to buy it only if Cooper would star. In September 2012, David O. Russell said he was interested in directing the film. On February 2, 2013, Chris Kyle was murdered. On May 2, 2013, it was announced that Steven Spielberg would direct. Spielberg had read Kyle's book, though he desired to have a more psychological conflict present in the screenplay so an "enemy sniper" character could serve as the insurgent sharpshooter who was trying to track down and kill Kyle. Spielberg's ideas contributed to the development of a lengthy screenplay approaching 160 pages. Due to WB's budget constraints, Spielberg felt he could not bring his vision of the story to the screen. On August 5, 2013, Spielberg dropped out of directing. On August 21, 2013, it was reported that Clint Eastwood would instead direct the film.