Various characters refer to the murdered police officer as John W. Bundy, but the police record of the case shows his name as W.W. Bundy.
In Springfield, when the technician who received the fax places the photo paper into the developer, he does so with the curled edges pointing down (so the image would have been formed on the outside of the cylinder. However, when the fax is developed, the edges of the paper curl point up (as if the image is formed on the inside of the cylinder).
When Jim wakes up after a rough night and goes to the living room and sits at the puzzle, he lights a cigarette with his right hand. When the camera changes and shots from the left from his wife's perspective, the cigarette is in his left hand. As the camera changes back and forth, the cigarette changes from his right to his left hand.
When Frank takes the lie detector test he tells the operative he is 5 ft 9 inches tall. Later when McNeal finds the arrest card, it describes Frank as 5 ft 8 inches tall.
When PJ talks to Frank in the prison hospital Conte's hands are on the table when the camera is on him but when it's on James his hands are in front of him.
When Reporter McNeal is doing his extensive footwork in searching for Wanda Skutnik in the Back of the Yards neighborhood, he is told to go to an address on Honore Street (a real Chicago street name). However, the guy relating this information pronounces it as "Huh-nor". The street name is derived from a French surname and is correctly pronounced by the locals as "Ahn-oree".
The photo is inaccurately said to be enlarged 100 times, 140 times, or more. The enlarged photos aren't zoomed in anywhere near 100 times.
The title is a misnomer. Telephone exchanges at the time of the story were always spelled with the first two letters in caps, i.e. NOrthside, followed by four, not three numerical digits.
In the film's opening narrative, the audience is informed that in 1932 there were 365 murders committed in Chicago: "one for each day of the year." However, 1932 was a leap year and, therefore, had 366 days.
Part of a story is shown being set in type by a Linotype machine. It may be read correctly, but if it were printed that way, it would show as mirror writing.
When McNeal first visits Tillie, he has no camera nor a photographer with him. The next morning, city editor Kelly is holding a paper with a photo of Tillie scrubbing the stairs. However, it is possible that McNeal sent a photographer back after meeting Tillie, since when he first met her he wasn't sure she was the right person.
At some point in this film someone refers to Soldier Field as 'Soldiers Field' - a mistake that a Chicagoan would not make. However, there is a feature of Chicago neighborhood slang of adding an unnecessary possessive "s" to the name of local institutions: somebody going for groceries at the Jewel Food Store chain would say they were headed "by the Jewel's."
Continually throughout the film, McNeal incorrectly refers to Springfield and Joliet as "up there", when really these cities are southwest of Chicago. Then, when visiting Springfield, he incorrectly refers to Chicago as "down there" while Chicago is really to his north. This is the opposite of how Illinoisans would refer to these areas. Springfield and Joliet are south of Chicago and are always referred to as "down there" or, more often, "downstate," from a Chicagoan's point of view. When visiting Springfield, you'd go back "up" to Chicago. Illinoisans' terminology of "up there" and "down there" always respectively follow the north and south directions of the map. In addition, when Kelly says he stopped at the prison outside Joliet while on his way to Decatur, McNeal suggests this is just an excuse as Decatur is in the opposite direction; in fact, Decatur is in central Illinois, and Joliet would indeed be on the way there from Chicago.
Wanda's Grocery at 1226 S. Ashland is shown to the right of address 1224. This is opposite from how even-numbered addresses are arranged on the south side of Chicago.
There was enough of the newspaper showing by the newspaper boy to identify the issue date without seeing the date due to the images shown below the headlines. They just needed to match the pictures in the newspaper held in the background to a newspaper from the same date and see if the photographs match.
Look at the example from the photographs for the film (slide 93 of 118). There is enough to compare newspapers.
Look at the example from the photographs for the film (slide 93 of 118). There is enough to compare newspapers.
To create a very tense scene, as the final enlargement of the photo is being transmitted, P.J. McNeal says he doesn't know if it will provide the proof they need. However, Brian Kelly had already seen the final enlargement before transmitting it, and he was on the phone with Stewart. He simply would have told Stewart that the enlargement worked and then gone ahead and transmitted the photo as confirmation.
When McNeal is interviewing Helen Wiecek Rayska, prior to the arrival home of Mr. Rayska, Helen indicates that she only divorced Frank Wiecek AFTER Mr. Rayska had met and began loving her and her son, Frank Jr. However, when Mr. Rayska and Frank Jr. arrive home after that point in the interview, Mr. Rayska tells McNeal with certainty that he never even met Helen and Frank Jr. until after the divorce was finalized, and that he could provide proof of that.