Jerry Lee was played by Rando, a 3-year-old German Shepherd from West Germany. A year-long search was held to find the right dog for the role. Over 40 dogs were considered but none of the American German Shepherds were deemed suitable. Rando trained for 3 months with Karl Lewis Miller and learned to understand commands in English.
At the dinner party given by the gangster, there is a butler walking across a room behind a doorway. The butler was Michael J.R. Gill who was working with the catering staff hired for the film. After the filming, he actually served the food used in the scene to the cast and crew. Gill was not an actor, but was actually a real English butler and for seven years was butler to British actor Laurence Harvey, prior to his death.
The trivia items below may give away important plot points.
Rando, while playing Jerry Lee, added his acting of faking being dead or asleep after he was brought out of surgery into the recovery room. It was not in the script. When the crew saw Rando adding his act while filming, it was so hiliarious and the camera crew was in a perfect positions at the right time in the right angles that it only took one try capturing him being sneaky.
Two versions of Lyman's death scene have been broadcast. In the first, when running towards a helicopter, he shoots Jerry Lee and is subsequently shot by Dooley. In the second, he shoots Jerry Lee and is then shot by the escaping helicopter crew.