You know what is troubling? Radio ask about someone being 'Killed.' That implies an act of murder. Had you said 'Died' that would be a bit more innocent. If you DO kill someone in the ocean I don't see why anyone would ever find a body. Just take a lesson from the Sopranos when they whacked big puss and dumped him in the ocean. All you would have to say is you went down off your watch and when you came back on deck no one was there! Spooky, and no way to disprove it unless you screw up!
Why do I feel like I just helped someone plan a 187?
There was actually a thread around here that was about a story where that exact thing happened. Some dude sailed into port and said the skipper of the boat had gone over several days before during a night watch. People wondered why he didn't call it in and just kept sailing for several more days. Don't remember how it turned out.