If you can get past the improbable key to the mystery, the rest of the movie has some good, strong points. The first twenty minutes plunge us into McCarthy's nightmarish events that may or may not have actually happened. We don't know for sure and neither does he, but there are the scratches on his arm. Did he kill those people or not. The surreal effects are impressively done.
McCarthy delivers a gripping performance, as good as Invasion of the Body Snatchers (also 1956), and much better than expected for a B-movie. In short, he makes us believe that his dilemma, however improbable, is real and not just a story construct. Without that intensity drawing us in, the movie would, I think, amount to little more than a mildly interesting walk-through.
The New Orleans locations provide a clever anchor to the real world, and a good setting for the colorful jazz scenes. However, a 63-year old Robinson is at least 10 years too old for the brother-in-law part even though he manages the cop role well. And can we really believe the chance occurrence onto the scene-of-the-crime mansion in all that unfamiliar backcountry. Unfortunately, the script requires more than just an ordinary suspension of disbelief. Too bad the script couldn't work in more bayou scenes. Those coming at the end are really creepy and nightmarish in their own right. Too bad also that the excellent McCarthy made so few films, preferring, I gather, stage productions instead. All in all, an interesting if regrettably flawed little movie.
