There's a physician who is seeking to deduce, why villains, rogues and miscreants are induced, into a life of crime, breaking laws most of the time, has a theory that he's willing to enthuse. Before he does, he gathers data on the flawed, encouraging a gang to break the law, as they do he takes their pulse, monitors things from their skulls, all the time he's making notes of what he saw.
It's not the best but it's not the worst, entertaining in places but quite ridiculous in part, Edward G. Robinson is always entertaining and Humphry Bogart bides his time once again, waiting for the big one, although he reaches his nadir the following year with The Return of Doctor X!