An especially good casts helps lift Republic's Secret Service Investigator well above the norm. Lloyd Bridges plays disillusioned ex-GI Steve Mallory, who falls in with a gang of wily crooks. Convincing Mallory that they're U.S. secret service agents, the villains persuade our hero to help them in a phony rare-coin scheme. When he realizes he's being flim-flammed, Mallory risks his neck by agreeing to work as a double agent for the real Feds. The film is effortlessly stolen by George Zucco as Otto Dagoff, the erudite but slimy head of the fake-coin racket. In case there's any question that Secret Service Investigator is a Republic film, the presence of Roy Barcroft as one of the heavies should remove all doubt. ~ Hal Erickson, Rovi