Prosecuting no body cases always present unique challenges. Defense attorneys often push the narrative that the deceased might not even be dead....
BARD is a high standard. Circumstantial evidence is weighted equal to direct evidence, but circumstantial evidence can also recall layers of connection. Linkage by inference.
Imagine for a second a wrongful civil lawsuit against CB, where the standard isn't BARD, but lower.
Does a phone call place CB outside the zone of possible abductor? Or was he burgling in one locating while his phone was establishing an "alibi" across town? Does he have a documented history of theft, breaking and entering, shocking sexual behaviors, etc, etc.
Has someone seen photos that link CB and MM? Photos that haven't been recovered but testimony that is evidentiary, a witness to the photo whose recall of it relates it to other known photos of CB, a common and identifiable backdrop, which depicts sexual violence that is not consistent with life/survivability....
I believe that MM's broken parents have seen enough to accept the bitter truth that MM couldn't have and didn't survive and that CB is linked to that. BARD for them, just not quite BARD yet, for conviction.
LE can continue to investigate, make more connections to continue building a strong circumstantial case against him because, for now, he's going nowhere. No reason to start the clock since he's in jail already.
JMO