The Invisible Killer is typical fare from Poverty Row. It's a mystery with a slightly misleading title and even though it has a short running time, there isn't many thrills to be had. This one is basically about a series of murders connected to a gambling racket. A couple of policemen from the homicide unit join forces with a lively girl journalist to solve the case. No surprises then. Even the killing method is not original even if it may seem bizarre enough to have to be. The murder method is a tiny poison pellet launched via a phone receiver when it is picked up by an unfortunate victim. This ridiculous killing method was used in the earlier movie Murder At Midnight (1931). You would have thought once would have been enough for such nonsense!