Character mistake: Carl, carrying his gun, goes up the outside staircase before entering Frank's apartment. When he encounters the frightened cleaning woman, he flashes his F.B.I. badge at her to identify himself. However, he only shows her the back of the black I.D. wallet, which has no markings on it.
Character mistake: Although great care was taken to duplicate Bob Crane's distinctive hairstyle for Greg Kinnear, Bob Crane's hair was actually parted on the left. The makeup department for this film parted Greg Kinnear's hair on the right, producing a mirror-image of Bob Crane's hairstyle.