Strangers on a Train

“The abiding terror in Alfred Hitchcock's life was that he would be accused of a crime he did not commit. This fear is at the heart of many of his best films, including "Strangers on a Train", in which a man becomes the obvious suspect in the strangulation of his wife. He makes an excellent suspect because of the genius of the actual killer's original plan: Two strangers will "exchange murders," each killing the person the other wants dead.”