Lang did everything right to set a tone of fear and dread. There's something about the use of silence that creates a sense of foreboding. I can't help but think that the placement of the camera, as well as the angles, just off in the distant make me think that you're looking at the scene through the murderer's eyes. Really inventive stuff. Lang's use of shadows and lighting, and the ability to create a dark atmosphere and such a sense of impending doom at the outset of the film had to contribute greatly to the film noir style.