Detective Comics #173

With his Van Cleer alias lost to him, Killer Moth decides to steal the identity of Bruce Wayne (whom he imprisons in a vault), then hires a plastic surgeon to alter his face into an exact double of Wayne's, and fools Dick Grayson into believing he is Wayne and Dick doesn't realize at first. The Moth goes out as Batman, enhancing his criminal reputation by making it appear that Batman fears the Moth. Wayne escapes in time to see Killer Moth shot down by one of his own gang, thinking he's been double-crossed. Moth's face is wrecked by the bullets, and the resultant cranial injury causes amnesia.