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 shows a man stabbing another, and the other images offer clues to the location of the event. A man attempts 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 took the photos before disappearing. Together they search the countryside for Ernest, uncovering that he may be involved in a jewel robbery and murder, and that the police are also after him. Their investigation leads them to a local inn where Mary misleads John, later confessing she was protecting her brother. They discover evidence that Ernest was trying to expose the thieves by setting up his camera to capture them, and the camera recorded the fatal struggle. Ernest is arrested but later confesses his role in the crime. John suspects the investigating policeman might 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.