I don't usually comment, but this keeps coming up and back around every couple of pages, so here's my opinion for what its worth:
Chief Walker and CCPD are focused on the house (and surrounding area) because that's HIS main target. As he's said repeatedly, that's where the boys "went missing", and his job is to find out why/how/who/whatever. In view of the fact that they've turned up practically nothing (as we have been told...or maybe there is more and he's not saying, which is his choice), now I think he is making d**m good and sure they have an airtight case for them never being there at all IF they are found elsewhere. No scent trail, nothing of them at the house, etc. If it ever gets to court, he can say, we did all but tear that place to the ground. They weren't there, and we have no clear path out the back gate.
Pointless from us looking in? Maybe. But its hard evidence of where they aren't. We know they definitely weren't buried in the backyard. That's more than has been shown in other cases, right?
I can't imagine they aren't checking out the Bakersfield apartment, etc. But that's BPD's jurisdiction, so the onus is on them to do due diligence checking things out from their end. It would be lovely to have more info from the Chief from that end of things, but again that's his decision as to what he feels can be released.
All of this is JMHO. The chief seems like a good guy, and I sincerely hope this comes to a good resolution for all of us who care about the boys. At the very least I hope they can find them and bring them home...even if they are no longer with us.