Tomorrow at Seven

Tomorrow at Seven is a 1933 American PreCode film directed by Ray Enright, by MampA Alexander Productions, Inc.

The coroner finds a letter on the dead man which is to be read if Winters dies. It will reveal the identity of the Black Ace. Clancy starts reading it aloud and unsurprisingly the lights go off and the letter has vanished when the lights are turned on again. People locked in their rooms that night and Neil has a hidden car outside signal to him.Later that night, the coroner turns up, the real one. Neil goes to Marthas room and asks her what she did with the letter, guessing that she had taken it because was afraid her father might implicate himself with the Black Ace. The letter is gone from where she hid it and all there is, is two sheets of plain paper and a Black Ace card. Clancy and Dugan appear and blame Neil. Clancy and Neil at gunpoint go to Drakes room and while Clancy is hurling accusations, there is a groan from next door and they find a dead man there Henderson. A search of Neil reveals he has a skeleton key so might have been able to enter the dead mans room. ........

Source: Wikipedia