Currently, it is stored in their hot/cold wallets so it's safe to assume money belongs to them. They aren't going to donate it to a charity if the case is not resolved anyway!
Well, I know about how they will store and stuffs. My point was - if they can not find a valid owner then the Bitcoin should send back to the address where it came from and guess what they won't do that. Keeping 5 Bitcoin or any amount which is not actually their, is kind of taking advantage of the situation.
How would you explain it legally? I hope now you understand what I meant.