I remember an old black and white movie I saw, in the English language and on TV, where the main character is being detained somewhere, possibly on an island, but he is never able to find a way to escape. I think he is doing forced labor, and I also think he is trying to re-unite with a woman.

At the end of the film, he figures out a way to escape. He simply begins shouting that he is a murderer. In the next scene, he is no longer in detainment. I think it might show a newspaper headline as well reporting his claim that he is a murderer.