When Columbo is driving the driving instructor, a car pulls out and the scenery is of city landscape, but when the camera is back on the driving instructor, the scenery is a neighborhood, and when the shot is of the two in the car again, it is city scenery.
As Galesko views the photos Columbo gave him from the funeral, he comes across the discarded photo of his wife tied up. From Galesko's point of view, the photo is pristine, with no signs of it being crumpled. The view from behind the photo shows definite signs of crumpling.
Sgt Hoffman gets a phone call and summons Columbo back into the office. When Columbo comes through the doorway, his tie is outside his collar. In the next shot, however, the tie is completely inside the collar.
As Columbo is driving Mr. Weekly back to his office, he makes a wild right turn. As he enters the turn, he has a cigar in his mouth; when the camera shot changes, there is no cigar.
When Mr. Weekly walks to get a lift from Columbo, there's a car parked in front of Columbo's car. When he finally gets inside and sits, the shot shows that the other car has vanished.
The reflection from Mr. Weekly's glasses reveal they are perfectly flat, meaning he doesn't require glasses. Presumably, they're to make him "nerdier" looking.
When Paul takes the two pictures of his wife, he takes them from the same place in the room, but the angles in the photos are different.
When Paul Galesko first starts to tie his wife up, the first shot of him is printed backwards as his hair is suddenly parted the other way.
Paul Galesko uses a German Luger, made mostly between the early 1900s through WWII. This type of gun has a toggle action, which is held open and up after the last shot, or when one cocks the gun on an empty magazine, and it's up just before he shoots it. The gun cannot be shot in this condition unless the toggle is pulled back and released with a magazine that's got at least one round in it. This is akin to trying to shoot a modern gun while the slide is locked back after the last shot. It must be released first on a magazine with rounds in it. If locked up and open, the gun won't even go "click".
When Columbo visits the real-estate owner Mr McGruder at the small cottage murder scene. The finger-print expert tells Columbo 'Im picking up prints all over the place'. As Columbo examines the fireplace, the print-man has an arguement with an invisible voice; a person who is not present in the cottage.
When Columbo is driving up the hill at the salvage yard toward the murder scene, the sound man's hand holding the boom mike can be seen in the lower left part of the screen.
At the end, when Galesko grabs the camera from the shelf full of cameras, Columbo views this as proof of his guilt. As that was the only camera of that particular type on the shelf - a Polaroid Land roll film camera - and since the photograph in question was taken by that type of camera, any knowledgeable photographer would have chosen that camera. However, there is at least one other camera similar to the Polaroid to the right of the one Galesko takes from the shelf.
Also, even though the original photo was destroyed, simply returning to the scene would have shown that the fireplace was on the opposite side of the room, proving the image had been flipped. However, as he does with many suspects, Columbo was counting on Galesko to jump at the opportunity of making a fool of Columbo and prove his innocence by putting him in a high stress situation of being taken in to custody based on false evidence.
Also, even though the original photo was destroyed, simply returning to the scene would have shown that the fireplace was on the opposite side of the room, proving the image had been flipped. However, as he does with many suspects, Columbo was counting on Galesko to jump at the opportunity of making a fool of Columbo and prove his innocence by putting him in a high stress situation of being taken in to custody based on false evidence.
When Sgt. Hoffman hands the ransom note and photo to Columbo, he tells him to be careful as the labs boys haven't examined it yet. At which point Columbo handles them with his bare hands and even pushing his finger on the photo to point something out.
The fastidious driving examiner Mr. Weekly tells Columbo about a driving exam accident he had "yesterday". This contradicts the DMV clerk's earlier statement that Mr. Weekly had come back to work that morning after having been out of town on previous days.
Columbo asks Sgt. Hoffman and another detective if they just saw what Galesko did. They did. Columbo then asks the property room attendant if he saw too. He says that he did, but he was sitting down, around the corner, behind the second detective. He may have heard what happened, but he wouldn't have been able to see it.
When Paul Galesko (Dick Van Dyke) picks up the gun to shoot his wife (Antoinette Bower), she reacts far too quickly to the "sight" of the weapon. She could not possibly see the pistol, as it is shielded by the lid of the briefcase that it was stored in.
When Columbo is explaining to his Captain that it would be unusual for somebody to use cabs rather hire a car, he begins to ad lib a little too much, and the stern-faced Captain struggles to contain his laughter.