The sweetness of strangers (1997)

Once upon a time very much alike the twenties in Germany, a little town is frightened to death by an uncaught child murderer. Since somebody has to be blamed the townspeople turn against an inconspicious policeman, a family-man who becomes suspected of the crime and therefore loses his job. Strangely enough, the only work he can find is to distribute candy on children, dressed up as clown. When a bunch of kiddies, including his own son who doesn't recognize the father due to the masquerade, plays a nasty trick to him, things turn really ugly...