what witness statements?
No one actually witnessed her dying by cause of him.
You have people on the boat, but they didn't witness it. They only told the police what the husband told them and that they thought it was bogus. But anything else is "hearsay".
The only real witness is the one who witnessed the "Bear Hug". But apparently didn't pay attention to what happened after the bear hug was over. So they can't be sure either.
Yeah he's guilty. we all pretty much agree with that. But no one witnessed him killing her, thus showing the possibility of 'reasonable doubt'.