Factual error: The murder is solved based on the time the Chinese pulled out of the Olympics. (The episode was from 1975, so it must be the 1976 Olympics.) The Chinese never pulled out of the Olympics or threatened to do so. Taiwan was kicked out of the Olympics by Canada, but Columbo mentions that it was Peking, that is, Communist China.
Factual error: Columbo asks for a red wine. His host orders a Beaujolais but the butler brings a Bordeaux. Beaujolais is from Burgundy, not Bordeaux. (01:18:40)
Factual error: Columbo is sent to investigate the murder of a man near the Santa Monica Pier. Santa Monica has its own police department. The LAPD has no jurisdiction there.
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