If they do find her under concrete, would a lot of physical evidence be destroyed? Just wondering if they’d even be able to tell COD.
If she's on the ground, under concrete and they remove the concrete properly, a ton of evidence will be preserved. For one thing (TMI for some): there should be way more than bones; there should be muscle and skin tissue. Rigor doesn't set in right away, but they should be able to tell if it had (eg., how long after death she was put there, whether she was moved - she certainly wasn't in the position she was in when she died).
Unless the perp did all of this very quickly (before cadaverine was being produced by the body - 12-24 hours after death), there will be telltale signs in his/her vehicle. Also, there will be Suzanne's DNA in the vehicle of transport, unless great care was taken with bagging her before transport - in which case, I predict that the body is still in that bag. It would taken quite the preplanning to figure out how to get a bag for a body, where in that body never touched the outside of the bag at all (so I believe there will be transfer DNA in the vehicle).
If our working hypothesis is that this hapless resident near Salida was having concrete poured, I wonder what time of day the concrete was actually poured. Someone must have been sweating bullets until that was done.
What's weird is that criminal minds almost always hop along to the "next big set of problems" rather than working out an actual plan. If Suzanne is in that person's yard, under concrete, and that place is associated with her husband's worksite (or is the worksite of any of his friends), someone would begin sweating bullets again.
I also bet by now the perp has given telltale signs to friends or family who have been in denial about it. Will they come clean now?