Song of the Thin Man confesses to both killings and pulls out a gun. An enraged Phyllis shoots him first, but her husband is only wounded. Then, despite Nick's pleas, she fires again and again, finishing the job. This "Thin Man" movie differs in several respects from the others in the series, and was one of two films in the series not directed by W. S. Van Dyke, who died in 1943. The script was one of three not written by the husband and wife team of Albert Hackett and Frances Goodrich, who had worked with Dashiell Hammett to develop the Nick and Nora characters
Thin Man (nuclear bomb) materials react more rapidly and therefore more completely. It was decided that the plutonium gun would receive the bulk of the research effort, since it was the project with the least amount of uncertainty involved. It was assumed that the uranium gun-type bomb could be more easily adapted from it. The gun-type and implosion-type designs were codenamed "Thin Man" and "Fat Man" projects respectively. These code names were created by Robert Serber, a former student of Oppenheimer's who worked on the Manhattan Project. He chose them based on their design shapes; the "Thin Man" would be a very long device,