I do share your doubts, to some extent at least. But to my mind there's no reason to expect the McCanns to prove their innocence (of a crime we don't even know has been committed: Maddie may yet be alive).

It's also highly perjorative to my way of thinking to designate someone an aguido, or suspect, when there's no defininte crime to suspect them of. And if you say you suspect someone of something, you can expect them to do whatever they can to allay that suspicion.

It's up to the prosecutors to find evidence with which to accuse them, and if they can't, there's no case to answer.

TYWD