The Donovan Affair (1929)

The lights go out at a high-society dinner party and one of the guests is murdered. The police are summoned and Inspector Killian shows up with his assistant Carney. In order to get a clear picture of what took place, Killany decides to have the crime re-enacted (with a substitute for the murdered man). The lights are turned out, and another man is murdered. This doesn't faze the Inspector one little bit, and he asks for a third re-enactment. The suspect list dwindles.