Henry Kendall & Ida Lupino in "The Ghost Camera" (1933) - a British Mystery Thriller

John Gray returns from a seaside holiday and discovers a camera has mysteriously appeared in his car. When he develops the negatives, one of the photos appears to show a man stabbing another, and the others offer clues to where the event took place. A man tries to steal the camera from John and takes the negative. After identifying the location of a woman in one of the photos, John tracks down Mary Elton, whose missing brother, Ernest, had taken the photos before disappearing. John and Mary search the countryside to locate Ernest, and as they investigate they discover he may be involved in a jewel robbery and murder, with the police also on his trail. This leads them to a local inn, where Mary misleads John and later confesses that she was protecting her brother. They find evidence that Ernest was trying to expose the thieves by setting up his camera to capture them. The camera photographed the fatal struggle of the thieves, and Ernest fled, dropping the camera in John's car. Ernest is arrested but later confesses his role in the crime. John, suspecting that the policeman investigating the case might actually be the murderer, confronts him and uncovers the truth. The murderer is caught, Ernest is released, and John and Mary, now in love, become engaged.