Robert Walker wears an unidentified watch

Strangers on a Train (1951) is Alfred Hitchcock's thriller in which the charming psychopath Bruno Antony (Robert Walker) proposes that two strangers swap murders. Waiting outside a train station as his plan unfolds, Bruno checks his wristwatch. The watch sits on his wrist, no maker legible at this distance, so it is recorded as an unidentified watch with the frame kept as evidence.