Indeed. Which is why I find it incredibly stange why you continually seek to write CB off as a credible suspect. On what basis.... he hasn't been convicted of murdering anyone before appears to be the primary reason.
Upon that logic, we can expect murderers to become extinct in the near future since anyone who hasn't been covicted for murder beforehand is not a credible suspect in any future murder.
Strawman. Not even subtle either.
The point being, while we're box ticking, is that criminality is, as a rule, often predictable, with an escalation displayed when unchecked, often labelled 'criminal spin' - 'I can' moves to 'I must'.
There's nothing to suggest CB has escalated to murder. For a man who has apparently abducted and killed a child and, as is being proposed here, he may have killed before, he gets caught quite often having perpetrated other acts, but is somehow also capable of hiding two corpses successfully and has essentially got away with it.
Your boxes are not being ticked.