[bloak]

It's not hard to imagine circumstances in which the police get involved because there is initially some suspicion of a crime, the police do some investigations and then stop investigating because, although many aspects of the case remain mysterious, it really doesn't look like a crime any more. (Alternatively, if it was a crime then the main suspects seem to be dead anyway so we have better things to do with our limited resources.) In fact I'm fairly certain I've read about many cases like that. Journalists might continue investigating in order to sell books and articles and satisfy the punters' curiosity but the police are no longer interested.