Other mistake: In the home of a murder victim, Columbo presses the telephone's "redial" button to see who was called most recently. A seven-digit number is displayed but only six beeps are heard as the number is redialed. Later, attorney Oscar Finch places a call by dialing only five numbers.
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.
Other mistake: Kingsley doesn't know if his victim is married or unmarried, whether or not he has children, if he has a maid, but he brings a hand vacuum and empty vial to the murder to collect cat hair from the victim's cat to plant on Clifford's jacket.
Other mistake: Several of the English characters change back and forth between calling Columbo "leftenant" and "lootenant."
Other mistake: When Benedict puts his briefcase in the back of the Jaguar, the hatch does not close properly. It is still not closed properly when he picks up the car from the repair shop.
Murder with Too Many Notes - S13-E4
Other mistake: In the movie within the story the murderer repeatedly stabs the victim and pulls back the knife. Even after several stabs there is no blood on the knife.
Dead Weight - S1-E4
Other mistake: Columbia calls Helen Stewart from a pay phone. He dials only six numbers, not seven.
The Most Dangerous Match - S2-E7
Other mistake: The police photographer takes a picture of the garbage grinder. His camera has a flash, and the photo is indoors, but the flash does not fire.
Requiem for a Falling Star - S2-E5
Other mistake: Twice, Columbo tries to reach his wife via telephone. On the second attempt, he dials seven numbers but on his first attempt, he dials only five numbers.
Other mistake: In the dart scene, Columbo needed 66 to win, he missed his first two darts so only has one dart left, he hit the 25 or bullseye which is 50 but somehow wins.
Butterfly in Shades of Grey - S12-E2
Other mistake: Fielding Chase and Lieutenant Columbo are on a road in the mountains above Malibu and Chase's car will not start. He tries unsuccessfully to call the Automobile Club on his mobile phone. He tells Columbo the phone number is "555-4411" but each time he tries to call, he presses nine digits.
Other mistake: When Columbo is examining the crashed Jaguar, we see silvery tape around the opening where the smashed headlight had been. The tape shouldn't be there.
Dead Weight - S1-E4
Other mistake: Columbo goes into a diner and has a bowl of chili. The cook asks if he wants his coffee black. Later he asks if he wants cream and sugar in his coffee.
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.
Other mistake: Over a public address system, Cahill tells his staff to quit working on their World War III scenarios until "after lunch." He immediately returns to his office and the wall clock shows the time as 4:30.
Butterfly in Shades of Grey - S12-E2
Other mistake: Jerry Winters' mantel clock chimes four times but the clock shows the time as 3:59.
Other mistake: When Melissa sends Andy to have a shower we see that there are several sets of clothing in the closet. We see them again in her flashback when she awakes after being kidnapped. They have just arrived in the Bridal (Empire) Suite, and are leaving very early the next morning for their honeymoon. Why would those clothes be in the closet?
Answer: In the show, he was already a Lieutenant. A promotion would put him in the next rank up, which for the L.A.P.D. would be Captain. However, some of a Captain's duties would be overseeing other officers and ensuring they're compliant with policies, regulations, and standards. It would also most likely take him out of the field. This is something Columbo has no desire for as he rarely goes to police HQ's. Nor does he show interest in compliance and standards (for example, not going to his semi-annual evaluation at the firing range). However, he could still be assigned to a higher pay grade based on expertise, which is a form of promotion that does not include rank advancement. This would be going from Lieutenant I to Lieutenant II. I don't believe in the show it's ever started what his pay grade is. Although, in s02e01 (I believe) he mentions making $11K a year. Whether or not this was a true statement on his part, if you could find pay scale information for an LAPD Lieutenant in the 70's, it could give you an idea of his pay grade.
Bishop73