Tor Johnson is something else! This isn't a masterpiece, but entertaining enough for fans of B-movie noir. Good photography and a tight 1-hour format; when this came out, it was almost certainly shown after the "main feature", back in the days when you could go to the movie theater and they would show 2 or 3 films, a newsreel, and a ton of trailers or "previews". All for a 40 cent ticket!
Boetticher would of course go on to become one of the greatest directors in the world; a man who made tiny, minimalist westerns, stripped down to the bolts and rigged to engage without pretense the joists concerns of inwardly-divided civilization. Existential stuff, and effortlessly impossibly poetic. Well, BEHIND LOCKED DOORS is, err, minimalist and stripped down. Also adorably silly. But kinda brilliantly designed.