Continuity mistake: Viveca's beauty mark switches cheeks several times between shots while she talks to her assistant. (00:07:45)
Continuity mistake: Dr. Murcheson is not wearing gloves when he scrapes the women's faces. Then he goes into another room and removes a gray glove from his left hand.
Continuity mistake: Just before Viveca murders Martin Sheen, she scribbles an amount on magazine-her nailpolish is red. Seconds later after the murder with the microscope, Vera's nailpolish is a completely different color, mauve.
Continuity mistake: During his poolside talk with Nelson Hayward, Columbo carries a large cardboard box under one arm. His coat tail is hanging straight at his side in the master shot, but when it cuts to another angle, the coat is draped over more than half of the box. (01:15:00)
Continuity mistake: Just before the end we see a slide of Columbo looking at the lamp, but in the next shot of Columbo the slide is reversed.
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