A better-than-average crime thriller from Poverty Row company Monogram, the plainly titled Criminal Investigator (aka Crime Reporter) stars Robert Lowery in the title role, an intrepid sleuth who discovers that the two cases he has been investigating have something in common. A deaf-and-dumb inmate (Lawrence Creighton) possesses some of the answers to the mysterious slaying of Joyce Greeley (Vivian Wilcox), a lady with a past, and the hero quickly discovers that murderers Miss Drake (Jan Wiley) and Soapy (Charles Hall) are answering to someone of importance. But who? There is a damsel-in-distress (former child star Edith Fellows) to save and several red herrings to dismiss before young Bob Martin (Robert Lowery) can wrap up this particular investigation.