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.
Short Fuse - S1-E7
Plot hole: We are told several times that the road to the mountain house is very narrow and difficult to negotiate. How did the very large crane get there so quickly to lift the bodies after the crash?
Undercover - S12-E3
Continuity mistake: When Krutch speaks to Columbo on the phone about 40 minutes into the show, his voice sounds like he has a cold. Earlier and later in the show, his voice doesn't sound like that.
Character mistake: Columbo talks to the cardiologist. The doctor gives him information about his patient, Mr. Williamson. Columbo has no warrant, so the doctor is violating privilege. He wouldn't give that information to Columbo.
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.
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?
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.
Continuity mistake: When Columbo meets Goldie for the first time she is having a massage. She then proceeds to dress by tying a dressing gown with a bow at the front. In the next shot the dressing gown is open with the tie at the back.
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.
A Bird in the Hand... - S11-E3
Factual error: They are watching a football game on TV with The Stallions playing some other team. The game they are watching is actually a Canadian Football League game between the Edmonton Eskimos and the Saskatchewan Roughriders.
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: "Apparent" drowning answers your question - things are not always as they seem. Drowning could be accidental, but it could also be a murder in disguise. Moreover, the actual cause of death has not yet been determined - accident, suicide, murder, or natural cause (e.g, heart attack while swimming). Columbo would be there to investigate if anything looks unusual for it to be a mere drowning or if there is evidence or suspicion of something else.
KeyZOid
This was just on TMZ.com's "Aaron Carter Dead at 34" (11/05/2022): "Law enforcement sources tell TMZ... homicide detectives have been dispatched to the scene but we have no information or evidence of foul play. It's standard operating procedure for homicide detectives to investigate such [drowning] death scenes."
KeyZOid