Continuity mistake: A man enters Ness's office and throws a manila envelope on top of a sheet of paper. In the close-up, the paper transforms into a folded newspaper and the envelope appears perfectly lined on it.
Continuity mistake: In the elevator murder scene, in one shot there's not much blood on the wall, but in the very next shot there's much more.
Continuity mistake: In the final court case, as Eliot Ness escorts out Nitti, Ness's wife watches them leave and is wearing a brown and cream hat, with a brown jacket. When the case finally resumes and the guilt plea is changed, Ness's wife is again shown, except this time she's wearing a light blue hat with dark blue ribbon, a blue jacket, with a floral green and blue blouse.
Continuity mistake: When Malone takes the Untouchables to the post office on a liquor raid, he gives his shotgun to Stone and uses an axe to break down the door. When he reaches through the door to open it, the view switches to inside the room. Malone comes through the door with his shotgun again. There is no time for him to drop the axe and retrieve his shotgun. (00:35:25)
Answer: Ness was coming to Malone's apartment to discuss the information with him there, Nitti and his men just got there first.
Captain Defenestrator