This crime seems pretty vicious for just a utilitarian killing. Trying to get the other woman off of your wife's mind.
What I also can't figure out is, where are the bullets? There's multiple casings, in the mine and in the car, casings that were fired from a .22 rifle right. I don't mean the ten .40s, because the report also said they matched the head stamp on casings in the mine to casings from the car that were fired from the same weapon. Where are all of the bullets that came out of those casings? They match the rebar, the tire tread, the casings, but no match on the bullets, not even on the metal composition. So they don't have 'em.
Could he have removed them from her body? Why even do that, if he's confident enough that she'll never be found. Confident enough to drop the casings, the rebar, the tires, but he takes all the bullets with him? Why also, did he only drop half the casings. Why did he leave some in the car for them to match.......
The thought process here is SO out of whack.