Based on a true 1946 Hollywood Police Department case, "He Walked By Night" is an early attempt at a "police procedural" film. It has a semi-documentary look combined with many of the conventions of film noir (thanks partly to cinematographer John Alton). Many of the outside scenes were filmed in or around actual locations. Richard Basehart plays a loner who is well-versed in electronic technology, guns, and police procedures. He's able to stay one step ahead of the cops because his paranoia and attention to detail keep him in a constant state of alert. It's also helpful that he listens in with his police-band radio. For a time he confounds the Hollywood cops because he changes his modus operandi. He begins as a break-in artist who steals electronic equipment, but when he kills a suspicious young policeman and loses some of his tools, he turns to armed robbery of liquor stores. Nobody can find him because he travels through Los Angeles in its underground storm drains, where he has hidden stashes of guns and other survival equipment. We also follow the cops as they make use of whatever little information they're able to gather on Basehart's character, and slowly they do close in after several missed opportunities and track the killer into the storm drains, where the play of light and shadow really takes over. One of the cops in "He Walked By Night" is played by Jack Webb, and there's no question he got the inspiration for 'Dragnet" from this film. For starters, "He Walked By Night" begins with a sky pan of Los Angeles and scenes of everyday Hollywood while the narrator gives a kind of "this is the city" speech. The police scenes are often very quotidian (sometimes to the point of being overly detailed), with cops tossing in small talk like "how's the missus? glad to hear it" before they ask other questions. Much of the pacing, attitude and overall feel of "Dragnet," which began as a radio show a year after this film and then moved to TV in 1952, is already here. The final scene in Los Angeles' storm drains ("seven hundred miles of hidden highways," according to the narrator) provides probably this film's most memorable images. Its set-up and execution are remarkably similar to Orson Wells being chased through the sewers of Vienna in Carol Reed's "The Third Man," which was filmed a year later and likely inspired by "He Walked By Night." And who knows, it might also have given a few ideas to the makers of "Them" a couple of years later when they revisited the L.A. storm drains with their giant ants. Ultimately, Basehart's character remains an enigma. We never learn that much about him. "He Walked By Night" isn't a great film, but it's an enjoyable look at postwar police work and primitive forensics.