Blooper

At the 40-minute mark, as Jeff Carter is walking through a doorway he removes his hat twice.

After Dr Randall's butler is murdered the newspaper headline spells the word 'Clue' as 'Clew'. The latter is an old-fashioned spelling of "Clue" that was still occasionally used in the early 20th century.

At approx. 12:30-13:38, while Jeff Carter and Billie Mason are conversing, tell-tale shadows move in front of them across the hood of the car until a large one appears at the end of the scene..