I can see I'm in the minority here (heck, maybe a minority of one), but this whole thing is not adding up to me.
First, from the very beginning--day 2--the sheriff has clearly focused on the husband as the perpetrator of a crime and has not investigated this as a mysterious missing person case. No "here's a description of missing woman and her bike," no "did you see this person on May 10 in this vicinity?" nothing like that. Early on, he searched water that could only have been either a dumping place for a body, or a search for someone who had, either intentionally or unintentionally, engaged in self-harm. Almost a week later, he halfheartedly asked for neighbors to "preserve" their camera footage--didn't even ask them to look at it! And specifically told them NOT to send it to him. He was certainly telegraphing that he didn't think it would be of much evidentiary value.
So he must know something that is pushing him strongly toward a crime. But then, it takes him nine days to get a judge to sign off on a search of the house! Nine days. Whatever he's seeing, that judge (or judges--can he shop that warrant to several looking for a signer?) took a long time to see. But he got it finally, carried out lots of items from the house but apparently there was no smoking gun. So now he responds to a tip and heads off to a site that, given the timeline and the state of construction, seems very unlikely to hold anything of value regarding SM's disappearance and starts breaking up concrete. This man is sure he's going to find something there. But he doesn't. Two full days of digging proves to me there's no body under that slab. And as someone pointed out earlier, they aren't looking for a body or body parts because the sifters aren't even suited up. Are they just saving face at this point?
There's just something wrong with this story. Doesn't mean I think BM is innocent. But does mean that I think LE started off with tunnel vision and it hasn't served them well.