Audio problem: The clock striking wakes Columbo, and he gets out of bed. We see that he is barefoot. He takes a few steps in the barrack room, and we hear the sound he would make if he were wearing shoes. Then the sound gets louder and has an echo when we see him outdoors on the parade ground (in shoes).
An Exercise in Fatality - S4-E1
Visible crew/equipment: When Janus parks his car at the health spa's service entrance, the reflection of filming equipment, including a large spotlight and the location's 9-bank array lighting, is visible on the car's surface. Then Janus lets himself in with his master key. (00:10:30)
An Exercise in Fatality - S4-E1
Visible crew/equipment: While Columbo (wearing gym clothes) is in the deceased's office, he questions Janus about the barbell and other facts in the case. When Columbo walks toward the door, the overhead moving boom mic casts a shadow on the wall at the top of the screen. (01:21:40)
An Exercise in Fatality - S4-E1
Visible crew/equipment: At Tricon, Columbo calls and leaves a message on Lewis Lacey's answering machine, then he heads to the elevator and grabs his cigar. When it cuts to Ruth Stafford at the piano, as she walks toward the door a T-mark is visible on the floor; then it's visible in following shots as well. (01:00:00)
An Exercise in Fatality - S4-E1
Visible crew/equipment: After Columbo follows Janus from the beach back to the house, Janus asks the detective why he's there asking questions. Then, when Janus walks into his house, the boom mic is visible over the open door (and through the top window curtain); as Columbo follows him inside, the overhead boom mic is now visible through the curtain over the door as it pulls away. (00:47:30)
An Exercise in Fatality - S4-E1
Visible crew/equipment: At the start, while Milo Janus is in Gene Stafford's office, Janus tells him, "Calm down, stress is bad for your blood pressure," and there's a visible T-mark on the carpet where Gene stands. When Gene walks back to his chair, another tape mark is visible on the carpet near the door. (00:03:20)
An Exercise in Fatality - S4-E1
Other mistake: It is made clear that the barbell weighs 180 pounds. When we see Janus put it across the neck of Mr. Stafford, he moves it easily, as if it weighs perhaps 30 pounds. Although we know that Janus is very strong, no one could move 180 pounds that easily.
An Exercise in Fatality - S4-E1
Plot hole: When Columbo finds Stafford's street shoes in his locker, they are tied. How did Janus get his shoes off without untying them? If Janus did untie them, why did he retie them before putting them in the locker? And why didn't Columbo wonder why someone would take off his shoes and tie them before putting them away?
Suggested correction: I'm not sure how this is a mistake. I always take my shoes off without untying them.
I can't take off my lace shoes without untying them. How do you do it?
Guessing by them not being tied too tightly. Depends entirely on how much give is in the shoes or the laces - it's certainly not unreasonable.
Factual error: In common with a number of characters in numerous episodes, Columbo hopelessly contaminates crucial evidence - at the end of the episode he handles the surgical gloves used by the killer with bare hands.
A Deadly State of Mind - S4-E6
Other mistake: Right before Columbo tricks Doctor Collier into incriminating himself, he places Collier under arrest, even showing him the warrant. At no time does Columbo inform Collier of his Miranda Rights; meaning that Collier's self-incriminating statements would not be admissible in court. Although the series typically features Columbo cornering the culprit in a way that is unlikely to hold up in court; this particular example stands out as Columbo has torpedoed his own case. If he had not placed Collier under arrest and let him incriminate himself then the statements (in front of witnesses) would be admissible as evidence.
Continuity mistake: Columbo is eating with the commandant of a military academy. Columbo has carrots on his plate, among other things. A few shots later, the carrots have been replaced with beans. The next time the plate is seen, it has carrots on it again. Later on in the same scene, the beans are back. Finally, at the end of the scene, there is a longer shot as the commandant is leaving the table, and where the vegetables were there is now something that looks like meat. (00:36:05 - 00:42:45)
A Deadly State of Mind - S4-E6
Plot hole: (Spoiler) Mrs. Donner screams in fright just as she jumps to her death from her balcony. This seems unreasonable since she believes herself to be going for a swim (under post-hypnotic suggestion) The scream is heard by a later witness to help establish time of death. If she suddenly realized the deadliness of her act, why would she continue with it?
Plot hole: When Columbo presents the flipped photograph to Dick Van Dyke in the final scene, Columbo insists it is correct and proves DVD guilty. But Columbo already showed him the rejected fireplace photo, which shows the room arranged correctly. It also shows the victim's wedding ring, which would be on the wrong hand according to Columbo.
Suggested correction: It's all part of Columbo's bluff: Galesko wants to get rid of Columbo as fast as possible and believes himself to be too smart, thus falls for it. Galesko might have forgotten about the fireplace photo or underestimated its importance. Even if Galesko points out the rejected photo: Columbo is already bluffing about the first photo, he can very well just claim the second photo never existed or is destroyed too, leaving Galesko in the same position as he is before he incriminates himself.
A Deadly State of Mind - S4-E6
Continuity mistake: When Columbo asks if he can borrow the psychiatrist's lighter, the man has his cigarette in his mouth and a newspaper in his left hand as he reaches into his pocket for the lighter. In the next shot, as he hands the lighter to Columbo, the cigarette has jumped into his left hand with the newspaper. (00:27:40)
Continuity mistake: When Columbo is talking with a cadet, Columbo says that he was in the army. Later, when the Colonel mentions 2200 hours, Columbo asks him what time that is. If Columbo had been in the army, he certainly would have known that 2200 hours is 10:00 PM.
Factual error: Several times, the revolver used to murder the singer is referred to as a "Weatherby" or "British Weatherby." Weatherby is an American manufacturer of rifles and shotguns; they do not make handguns. The revolver used is a Webley, which is of British manufacture.
Other mistake: When Rosanna's body is brought to the ship's medical room, the doctor confirms that there are no bruises on the body, but she had been forcibly slapped in the face earlier that day by Mr Danzinger (Robert Vaughn). The slap was hard enough to knock her over therefore a bruise should be visible, even through make-up.
Plot hole: The cruise ship is sailing from LA to Mazatlan in Mexico. Looking at a map, the ship will hug the west coast on its journey therefore is never far away from land. The murder takes place on the first evening of the cruise only a few hours after setting sail by which time they won't be far from San Diego. Why didn't the captain order the ship into San Diego or another suitable harbour and let the police take over the investigation?
