Corrected entry: During the opening credits, the film of a fountain in front of a mansion is running backwards. The water is flowing upwards from the pool back into the water jet.
Corrected entry: Lauren Dayton has a package sent to Columbo. It contains a bed for his basset hound. Later when she meets Columbo at a restaurant and sees the box, she says, "You didn't open it." Since the box and the lid were each separately wrapped in red paper, there is no way she could have known if the box had been opened.
Correction: The film is not running backwards. It's called the "wagon-wheel effect" where the camera's film rate isn't fast enough to capture the flow of the water. This is a natural phenomenon and not a movie mistake, you can simulate the same effects with strobe lights or blinking rapidly.
Bishop73