Douglas Klump (Rick Gomez) is the first character seen with the Beretta "Auto 9", aka the RoboCop gun. Hartigan (Bruce Willis) later takes Klump's Auto 9 and kills a cop with it at the Roark's Farm. The Auto-9 seen in RoboCop was an actual Beretta 93R, but in the Sin City version of the gun, close inspection of the slide reveals a decocking safety of a Beretta 92FS, while a genuine 93R has a frame mounted safety, meaning this gun is a 92FS mocked up as an Auto 9. It was mentioned in a behind-the-scenes featurette that this particular weapon was used due to writer Frank Miller's involvement in the story for RoboCop 2 and RoboCop 3.