Continuity mistake: When Hartnett's character is having dinner with the Dahlia look-a-like's family, at one point he puts a forkful of food in his mouth and then his hand dangles there with his elbow on the table and the fork in front of his left shoulder. Cut to the next shot of the table and now his elbow is off the table and his fork is much lower and over his plate. The old man is talking the entire time so there is no time lag for him to have moved his hand.Guy
Revealing mistake: When Lee is being lifted into the incinerator, he moves his head, despite being dead.
Factual error: The Black Dahlia is shown smoking a "cork tip" filter cigarette. In the 1940s, cigarettes had no filters and the paper on the "stick" was all white.
Continuity mistake: In the scene where the three main characters are having dinner, Scarlet's character pours four glasses of wine for just three people.