If that swimmer is really the chef, based on that pool footage, he won’t win any “form” awards, but he can swim well enough to save himself, unless he panicked. Many people who can swim lose their heads when faced with a sudden or tricky water problem, and they easily forget to just flip over and float when they’re tired or panicked. Having said that, the odds are good that he was murdered because he knew or saw something TPTB didn’t want known or seen. They have so many ugly secrets, and place so little value on lives other than their own that they think nothing of solving their problems with a little murder.
I still want to know who the other paddle boarder was...