When Lois shoots her husband, he falls forward through the doorway and lands on his back with one foot upright near the door. But, in the next shot as it pulls back from a close-up of Ed, the position of the body has significantly changed.
Both Lee J. Cobb and John Dall pronounce Howard Frazer's last name "Frazier" a number of times, then switch back to "Frazer."
When Andy Cullen is stopped for running a red light, the motorcycle cop pulls up behind his car. The cop leans his motorcycle to the right and gets off to the right. When Andy leaves, the motorcycle is shown leaning to the left.
As Lieutenant Cullen and brother Andy are driving to the Frazier house, the car has no rear view mirror. After they park in front of the house, the car suddenly has a rear view mirror.
Towards the end, a very concerned Janet Cullen picks up the phone - before direct dialing came into use) to call her husband at work and CLEARLY says "Aperoter" (rather than "Operator"). Played it back 3 times to be sure.
The books where the bullet went are clearly props. There are three volumes of The Encyclopedia of Health, two of which are volume III and one is volume V. Five other books are volumes of the Cambridge History of English Literature, three of them being volume IX and two volume XI.
Lt. Ed Cullen's (Lee J Cobb) car is a coupe, but he gets into a 4-door sedan as he leaves the apartment after knocking out Andy.
Lt Ed Cullen's (Lee J Cobb) car is referred to as a Coupe, but it is a 4 door Sedan when seen as Cullen is leaving his apt after knocking out Andy Cullen.
When Janet stops Ed on the street, a reflection of a wavering boom microphone is visible on the hood of Ed's car.
As Ed and Andy walk along the sidewalk, a 1949 Ford coupe making a right turn in front of them runs over the curb.
When she calls headquarters looking for her husband, Janet asks for "Lieutenant Cullen." But that's her brother-in-law; she should have asked for "Detective Cullen."