Factual error: In a couple of scenes, most notably the one where Graysmith drives his kid to school, there are newer cars in the background than the year it is supposed to be. In this scene the car is a 1971 Chrysler, when the scene takes place in 1969.

Continuity: When Robert Graysmith is speaking with Sherwood in Sherwood's garden, Robert has his arms crossed. The watch on Robert's left hand changes multiple times between shots.

Continuity: In the shot where Robert Graysmith goes to see Paul Avery on his boat, the pong game on the T.V. in the background goes from 15:9 to 14:9 back to 15:9 between shots.

Continuity: During the scene when Graysmith and Toschi are having lunch, the burger Toschi is holding, and taking bites from, has lettuce hanging out of the bun in some shots, but not in others. Most of the shots from behind him show the lettuce, while most, but not all, the shots from the front don't have lettuce showing. He does put the burger on the plate a couple of times, but the lettuce is still inconsistent in what is meant to be a continuous action.

Factual error: Some of the computers shown in the scenes at the newspaper, set in the 1970's, are a newer style than what was available at the time. They look like they are from the 1980's.

Continuity: In the scene where Graysmith goes to Vaughn's house, his jacket is soaked from the rain. Moments later he is sitting in a chair, and we can see his jacket is dry. Not enough time passed in the film for the jacket to dry.