Goofs

The address (shown in the newspaper) of Richter's victim is 2401, but when the detectives arrive at her apartment, her address is actually 656, Apt. 3C.

When Cheryl first runs up the stairs of the building under construction, there are a couple of current-day cars and about a dozen spectators. A few minutes later on the top as she looks down, there are well over a hundred spectators, street flares, and several vintage 1930s-era vehicles, which indicate this is stock footage from a much earlier production.

When the police confront Cheryl Draper with the second letter she supposedly typed (with her typewriter present, to prove it matches), it isn't in the typeface of the letter that Richter retyped on her typewriter, but in the quite different typeface of his original typing.

(At around 15 min) Cheryl looks out her window into Albert's apartment across the street using binoculars. Then she looks to the right and notices the vacant apartment next door. Scenes in the hallway show that, as seen from outside, the vacant apartment is to the left of Albert's.

After Cheryl leaves the police station, believing that nobody believes her story, she's speeding around curves on a mountain road that's absolutely bone dry. In the shots where the police car is pulling her over, the roads are wet with rain, as they are in the following scenes where the police offers arrive at the apartment building to question the residents.

After Cheryl took the burned food out of the smoking oven, she set it on the kitchen counter, then put her fingers on the knob on the stove as if to turn the oven off, but she didn't actually move the knob at all - just pretended to. It was never turned on to begin with since the pointed edge was at the top, in the 'off' position, before she touched it.

The story is taking place in Los Angeles, but the map on the wall in Larry's office is that of San Francisco.

Cheryl lives in a luxury apartment in a metropolitan section of Los Angeles, yet for some reason has to drive down a winding deserted road to reach the local police station, which is also located in an urban downtown area.

When Richter arrives for the first time at Lt. Mathews' office, he greets Cheryl Draper by name, but he has neither met her previously (except as a shadow behind her curtain) nor been told her name.