In the scene in the coffee shop, a man in the background between the two main actors is noted "thug" character actor Harry Wilson.
Suspect Stash Erwin drives a reported gray colored 1956 Ford Sunliner Convertible to the Apex Plastics robbery location. Warren Siddons is also driving a gray colored 1956 Ford Sunliner Convertible when he picks up Suspect Erwin, who is hitchhiking. Both convertibles are probably one in the same with a simple license plate swap. Suspect #3 Gloria Burgess is driving a dark colored 1955 Plymouth Savoy 4 door Sedan when she leaves Warren Siddons' home. Officer Johnson is driving Dan Matthews around in a light colored 1956 Chevrolet 210 4 door Sedan.