a few were created on set. John Milius contributed dialogue polishes, and Sugarland Express writers Matthew Robbins and Hal Barwood also made uncredited contributions. Spielberg has claimed that he prepared his own draft, although it is unclear to what degree the other screenwriters drew on his material. One specific alteration he called for in the story was to change the cause of the shark's death from extensive wounds to a scuba tank explosion, as he felt audiences would respond better to a "big rousing ending". The director estimated the final script had a total of 27 scenes that were not in the book. Benchley had written Jaws after reading about sport fisherman Frank Mundus's capture of an enormous shark in 1964. According to Gottlieb, Quint was loosely based on Mundus, whose book Sportfishing for Sharks he read for research. Sackler came up with the backstory of Quint as a survivor of the World War II disaster. The question of who deserves the most credit for writing Quint's monologue about the Indianapolis has caused substantial controversy. Spielberg described it as a collaboration between Sackler, Milius, and actor Robert Shaw, who was also a playwright. According to the director, Milius turned Sackler's "three-quarters of a page" speech into a monologue, and that was then rewritten by Shaw. Gottlieb gives primary credit to Shaw, downplaying Milius's contribution. Casting Though Spielberg complied with a request from Zanuck and Brown to cast known actors, he wanted to avoid hiring any big stars. He felt that "somewhat anonymous" performers would help the audience "believe this was happening to people like you and me", whereas "stars bring a lot of memories along with them, and those memories can sometimes ... corrupt the story." The director added that in his plans "the superstar was gonna be the shark". The first actors cast were Lorraine Gary, the wife of then-president of Universal Sidney Sheinberg, as Ellen Brody, and Murray Hamilton as the mayor of Amity Island. Stuntwoman-turned-actress Susan Backlinie was cast as Chrissie (the first victim) as she knew how to swim and was willing to perform nude. Most minor roles were played by residents of Martha's Vineyard, where the film was shot. One example was Deputy Hendricks, played by future television producer Jeffrey Kramer. Lee Fierro plays Mrs. Kintner, the mother of the shark's second victim Alex Kintner (played by Jeffrey Voorhees). The role of Brody was offered