The film was originally released with a "Whodunit Break" gimmick. Right before Ann is seen firing the gun at Hugh, the action pauses and an off screen voice tells the audience that the film will pause for one minute to give them a chance to solve the crime. The previous murders are shown under a large clock ticking the minute away. After the narrator tells the audience they can figure the mystery out if they have "paid close attention" he finishes by intoning "DO NOT BE SURPRISED BY WHAT YOU ARE ABOUT TO SEE!" At that point the action resumes. Some video and TV prints do not contain this fun "murder minute", but others (including the version shown on TV in the UK) still do.
