A rather odd movie starring Lon Cheney Jr., a mobster (Cheney Jr.) is convicted and executed, and his body after is given to a scientist, who in his experiments exposes the corpse to a jolt of high voltage that brings him back to life and makes him impervious to bullets or stabbing, and the mobster goes after the lawyer and crime partners who betrayed and testified against him. And the police go on a citywide manhunt to track him down before he can kill again.
I would have gone for the movie title "The Frankenstein Mobster" but maybe that would just give it away.
An odd splicing of classic Hollywood film-noir of mobsters, gritty first-person narration and police detectives clashing with criminals in tough-guy dialogue, mixed with sci-fi/horror elements. But a fun mix. More noir than monster movie.
I neglected to include a link to the movie the first time I posted it. And here made it easier o see both the Wikipedia listing for he movie, and access to the movie itself. I've developed a recent new appreciation for the film noir genre, with classics like Casablanca, The Big Sleep, Dark Passage, Out of the Past, and more recent films hat are more recent tributes or expansions on the genre, such as Peeper (1975), Bladerunner (1982), and L.A. Confidential (1997)