Character mistake: Piloting a helicopter, Leslie ends a radio conversation by saying "Over and out." "Over" means "I'm done talking; please respond." "Out" means "I'm done talking and I'm ending this communication." An experienced pilot would never say "Over and out." They are two different terms.
Continuity mistake: When Columbo is eating his chili in the booth at the diner, whilst talking to the daughter of the murderer, his bowl of chili moves. It is right in front of him at one point but is then away from him. And it now contains less food.
Continuity mistake: When Columbo and the woman have finished flying in the light aircraft, she taxis the aircraft back and shuts down the engine. There isn't much to see behind the aircraft at this point, but when Columbo and the woman get out (in the immediate next shot) there are two rather large buildings/hangars which have magically appeared right behind the aircraft. Plus the aircraft propeller has changed to a more horizontal position.
Character mistake: The policeman gets the bag for the ransom from the wife of the kidnapped person, grabs it with bare fingers and puts the money into it - without gloves, too. (00:23:30)
Factual error: When Mrs. Williams takes Columbo flying, she does some aerobatics. Neither of them is wearing a seatbelt. No pilot would do that.
Continuity mistake: In the living room of their home, Lesley Williams shoots her husband in the chest. As he falls, he knocks a lamp off a small table. Lesley puts the lamp back on the table, but in all the following scenes in the living room the lamp is gone. (01:00:00)
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