CB appears to be a violent, indiscriminating offender. Young, old. He brokers IMO in shock and fear.
I've followed a case where CCTV captured a perp entering a home in which evidence shows a murder occurred. Although the perp left the home and the victim's body did too, CCTV missed it. So technically no proof he left, no proof she left, except that they weren't still there.
I follow another case where an individual faked her own kidnapping, describing in great and accurate detail her place of faked captivity, a crime exposed when LE gathered photographs of an actual room, depicting just what she described, only it was in the home of her ex-boyfriend.
LE doesn't have to show that CB was at the M's villa or how he acquired her to know that, somehow, he came into possession of her, and against her will, if they have a circumstantial case positioning him with her at a point in time. (They don't have to know how he did it for it to be still true that he did.)
And I believe they do.
I believe they have photographic evidence of MM in a state incompatible with survival at a location consistent with CB. Indirect evidence. Or better said, direct evidence, once removed.
I think another crime is key.
The same room, bed, device, for example, linked to a known crime and victim. Perhaps victim recall, perhaps different photographic evidence.
A simple if, then syllogism.
If CB commit a crime with Victim A in Setting B, and CB is in the frame in some fashion, then if there's a photo with Victim C in Setting B, although CB is not in the frame, his presence there can be inferred.
CB may never be charged with the crimes against MM because of the inherent challenges of no body cases and the steep hill of reasonable doubt, but no matter if he's held incarcerated on his other convictions.
I believe that LE -- and MM's dear parents -- are equally heartbroken and confident that CB is responsible for MM's disappearance and the threshold for BARD met. And I believe it's in the form of a photograph, showing inexplicable suffering, and also in the photograph enough accidental background to site it. And while CB himself is not visible in the photograph I believe exists, the background is identical to a known crime/locale.
And IMO if we saw that photograph, we'd understand. And be broken too.
Which is exactly how their most recent statement reads to me
CB is depraved. And he is guilty.
JMO