The intro narration to this film is priceless:
This is Los Angeles, or Our Lady the Queen of the Angels, as the Spaniards named her, the fastest growing city in the nation. It has been called a bunch of suburbs in search of a city, and it has been called the glamor capital of the world. A mecca for tourists, a stopover for transients, a target for gangsters, a haven for those fleeing from winter, a home for the hardworking. It is a city holding the hopes and dreams of over two million people. It sprawls out horizontally over 452 square miles of valleys and uplands, of foothills and beaches. Because of that large population, and because it is made up of people from every state in the union, Los Angeles has the largest police beat in the country, and one of the toughest. The lights on the complaint board flash 24 hours a day. Citizens reporting a lost child, an prowler, a man molesting a woman. Spend one hour here and you will think the whole city has gone berserk. The work of police, like that of woman, is never done.
When people hear the term “film noir” they usually think of Humphrey Bogart as Sam Spade, but for me, this film, which was the bases for the later TV series “Dragnet,” really comes closer to being a definitive noir film. The expressionistic lighting (in the naturally sunny city of LA), the hardboiled dialogue, the plot, and the climatic chase scene through the cavernous storm drains of the city all add up spell out the rules of the genre. Down By Law, No Country For Old Men, and many other films borrow shots directly from this somewhat obscure film.