CB's " relationship" with the 17 year old vacationer is both convenient and predatory IMO.
It is my belief that he used this girl because using people is what he does and to build out a cover. Man traveling alone might draw attention. Man traveling with an underage "girlfriend", sketchy. Man traveling with his "daughter" (or "niece"), carry on.
Atrocious story, probably its own thread here, lithe boy kills his neighbor girl playmate, hides her body under his bed. Carries on.
I think that CB's gall is exactly the trait that accounts for MM's disappearance. I think he could easily steal a child and walk away with her like she's his daughter and they're walking in the park on a sunny Sunday afternoon.
I think CB could easily hide a child for days, without anyone near him knowing, people who would feel strongly that he couldn't have done any such thing because easily (they think) they would have known.
I think CB gets off on that kind of trickery.
Near to me, a thirteen year old was abducted from her own home, both parents murdered, no trace of the suspect and LE was on site within 4 minutes. He held her captive, often wedged in under his bed, hosted his family at times, for 80 days. Sat visiting with his dad with a 13 year old upstairs under his bed. That is nerve. (She eventual rescued herself.)
Abductions can happen fast and without leaving evidence. Brazen captors aren't afraid to conceal living victims right under unsuspecting noses. It's part of the thrill IMO.
I will not be surprised if we learn that CB had MM in his van at the same time as a passenger, unaware. Afraid to be found out? No. I don't think he feels fear. Exhilaration. I think it's his kink. A thrill.
I think sweet MM had just the kind of nature that someone with CB's nature wouldn't think twice about exploit. Access to ether however better explains how he could keep a child quiet long enough.
IMO this is how he got her to his campsite, the one LE searched apparently in vain. If CB is going to bury a victim, he going to bury her under a dead animal. But why go to the trouble when he could weigh her down in water or toss her into a dumpster somewhere?
Often, children who are kidnapped are killed, within 24/48 hours, if not in the first.
CB seemed to have other designs. Deeply sadistic. How many days would he keep a little? As long as he wanted, if he didn't kill her first, subjecting her to worse things than I care to imagine.
I don't think CB would so much as flinch driving with a MM, dead or alive, through a police check point or border patrol.
It's a game to him.
JMO