An early Fred Zinnemann flick, Act of Violence (1948), is at least plausible: A vengeful lame man (Robert Ryan) with a nice girlfriend is hunting a married suburbanite (Van Heflin) who wreaked terrible damage by turning into an informer for the Nazis. Both men were in a German concentration camp; now Ryan wants to kill Heflin.
To me, this mere plausibility pleases less than the movie’s momentum—and Zinnemann’s control. How well he works with his actors! Ryan is perfectly somber without being a goon. Heflin is every inch an ordinary suburbanite reduced to a pursued wreck. Vincent Minnelli couldn’t get much energy from Mary Astor in Meet Me in St. Louis, but Zinneman does in this film.
Act of Violence ends with an unfortunate stinting on sympathy for the Janet Leigh character (who is married to the ex-informer), but at any rate Leigh, too, gives a committed, vigorous performance. And she looks like a million bucks.