The bumper sticker and the rear bumper of the car initially driven by Ethel Andrews was damaged when at the garage after the first accident although the rear of the Ethel's car was not damaged by running off the road with the front end. After they switched identities, and cars, when she turned around and passed her car wrecked and in a ditch, the bumper sticker and bumper were undamaged. The damaged bumper was clearly shown at the garage so there must have been a loss of continuity between what was supposed to have happened in the car accident.
After Ethel Andrews switches cars with Peggy Sutton, Ethel's Ford convertible develops a flat tire while she is driving. As the tire begins to wobble, a closeup angle shows Ethel looking over her shoulder while the front windshield has no rear view mirror attached to it. The following wide shot shows her pulling off the road, but now a rear view mirror is prominently attached to the windshield.
When Paul was talking to Mr. Park Milgrave about Peggy Sutton there's a stuffed owl and an ashtray on the table in back of the couch. Mrs. Althea Milgrave comes into the room and fixes herself a martini. She sits down on the couch next to her husband and when the camera has a close up, the owl and the ashtray are missing.
When Bruce Strickland is shot, the gun shown is a revolver with a silencer attached, and the sound of the shots is quite low. However, silencers are not effective with revolvers, as the sound escapes from the cylinder too, not just the barrel.
A burglar's POV of a box full of money shows real U.S. currency at the top of each bundle of bills. When the money is shown again a few seconds later, each bundle of bills is topped with fake stage money.
When Ethel Andrews looks up Perry Mason's number in the phone directory, the close-up of the page, which should be in alphabetical order, shows that the last name Masa is incorrectly listed *after* Masburn and Mason. In the next column the Macs are listed following Mazzola and several names and addresses that are above Perry Mason in the second column (Macklind, Mackson, etc.) are repeated in the third column.
A bundle of bills in Peggy Sutton's car doesn't look like real money; it's fake stage money.
Lt. Drumm described some burned money as being newly minted. That money, seen by the viewer before being burned, was obviously used.
When Peggy Sutton looks at Ethel Andrews' driver's license, the close-up reveals that it shows Ethel's month and day of birth (11/7), but not the year.
Why did the counterfeiter burn the money when he recovered it? He could have taken it to pass somewhere else or destroyed it later away from a crime scene.
It is never explained why Strickland was in Ethel's apartment when he was killed, or what he was looking for. Nor is it explained how he knew where Ethel was staying. It is also not clear why the police and Lt. Drumm, a homicide detective, were called to the scene, since neither they nor the motel owner appear to be aware that a murder was committed until after the door to Ethel's room is opened and they discover Strickland's body.
Perry has to prod Lt. Drumm into realizing that someone may have entered Bruce Strickland's apartment with a key taken from his dead body. Considering that there was no apartment key on Strickland's body when it was found, Drumm should already have reached that conclusion.
Mr. Caruthers, Miss Erskine and Mr. Strickland all say they knew nothing about Ethel planning to marry Strickland. They would certainly have been told about it by Rev. Alford, who was to have married them; the reverend even mentioned the intended marriage in Ethel's funeral oration.