Witness for the Prosecution

Charles Laughton, who could be moody and difficult, was apparently a dream to work with, throwing himself into the rôle with dedication and delight. Billy Wilder later recalled a day that was set aside just for shooting reaction shots of the jury and courtroom crowd (composed of extras hired only for the day). Normally, the assistant director would read the actors' lines, and the extras would react. However, Laughton, who was fascinated with the whole process of filmmaking, begged to help. So he came in on his day off and read all of the off-camera speeches to the jury members. He not only read his part but also the judge's, the prosecutor's, and even Marlene Dietrich's. According to biographer Maurice Zolotow in his book "Billy Wilder in Hollywood", "it was an exhibition of craftsmanship such as Wilder had never seen. He believes that Charles Laughton had the greatest technical range and power of any actor, man or woman, whom he has known."

(at around 1h 50 mins) The knife, being material evidence, would not be left lying on the table unattended after the case is closed and everyone has left the courtroom.

As the end credits appear on screen, an announcer's voice is heard: "The management of this theater suggests that for the greater entertainment of your friends who have not yet seen the picture you will not divulge to anyone the secret of the ending of Witness for the Prosecution."