Larry Hankin as Charley Butts Frank Ronzio as Litmus Roberts Blossom as Chester "Doc" Dalton Paul Benjamin as English Bruce M. Fischer as Wolf Grace Danny Glover as Inmate Production Screenplay and filming Alcatraz was closed shortly after the true events on which the film was based. Screenwriter Richard Tuggle spent six months researching and writing a screenplay based on the 1963 non-fiction account by J. Campbell Bruce. He went to the Writers Guild and received a list of literary agents who would accept unsolicited manuscripts. He submitted a copy to each, and also to anybody else in the business that he could cajole into reading it. Everyone rejected it, saying it had poor dialogue and characters, lacked a love interest, and that the public was not interested in prison stories. Tuggle decided to bypass producers and executives and deal directly with filmmakers. He called the agent for director Don Siegel and lied, saying he had met Siegel at a party and the director had expressed interest in reading his script. The agent forwarded the script to Siegel, who read it, liked it, and passed it on to Clint Eastwood. Eastwood was drawn to the role as ringleader Frank Morris and agreed to star, provided Siegel would direct under the Malpaso banner. Siegel insisted that it be a Don Siegel film and outmanoeuvred Eastwood by purchasing the rights to the film for $100,000. This created a rift between the two friends. Although Siegel eventually agreed for it to be a Malpaso-Siegel production, Siegel went to Paramount Pictures, a rival studio, and never directed an Eastwood picture again. Although Alcatraz had its own power plant, it was no longer functional, and 15 miles of cable were required to connect the island to San Francisco's electricity. As Siegel and Tuggle worked on the script, the producers paid $500,000 to restore the decaying prison and recreate the cold atmosphere; some interiors had to be recreated in the studio. Many of the improvements were kept intact after the film was made. Siegel's original ending closed with the guards’ discovery of the dummy head in Morris's bed, leaving it uncertain whether the escape attempt had succeeded or failed. Eastwood disliked this and extended the ending by having the Warden searching Angel Island and discovering a chrysanthemum on the rocks, a genus not native to the island but grown on Alcatraz by Doc, and later used