> What they can't do is prevent you from deleting your DMs if you know you're under investigation and likely to be caught

If you are pretty confident your under investigation then this is might be Obstruction of Justice and that's pretty illegal.

> But refusing to give up encryption keys and supiciously empty chat histories with a valid warrant is very good evidence of a crime in itself.

Uh, it absolutely isn't? WTF dystopian idea is this?