..... unless the McCanns confess.
..... unless someone confesses.?
.
Too narrow limits I am afraid.
Take the situation with "statement analysis"or whatever you wish to call it. Dr Leal is, according to the website I linked, currently a research fellow still researching "interviewing to detect deception". She was obviously confident enough of her research a year ago or so to appear on telly to state in her opinion Drs McCann were innocent.
Mr Hyatt it would seem, using basically similar techniques, is prepared to appear on telly stating the opposite opinion.
So from the same "dataset" we have two diametrically opposed propositions from two practitioners who are prepared to stick their heads up.
Until we are up around 91% of "experts" in agreement based on the same dataset, the beyond reasonable doubt threshold in English courts, then I would suggest what we are looking at is no better in practical terms than the investigating officers "gut feeling". I'll change my mind when we reach the 91%.