He Walked by Night

I saw the 1948 film noir, He Walked by Night. It was very well done. 

It stars Richard Basehart as Roy Martin, a former police radio specialist who becomes a burglar in post-war Los Angeles. It also stars Jack Webb, as the police lab scientist, and a very convincing performance by Whit Bissell as Paul Reeves, the owner of an electronics leasing business through whom Basehart is leasing his stolen goods. 

The film opens with Richard Basehart attempting to pick the lock on the door of an electronics shop. He is discovered by a police officer returning home. A confrontation ensues in which the police officer is shot and shortly thereafter dies from his wounds. 

This film was the basis of all the incarnations of Dragnet, which Jack Webb was instrumental in the creation of. There was apparently a 1950s radio version of Dragnet, as well as a 1950s television version, prior to the 1960s series starring Harry Morgan. 

The entire film is here on YouTube.