With the new information that AM thinks there was an abduction, plus what has been said about the locals being afraid, secrets in the mountains, etc, my theory has shifted a bit.
I used to assume that this was a typical husband decides to kill the wife story. But now...
* There may be some drug activity going on in town, which explains the fearful locals. Open secret? Intimidation?
* Probably meth, due to BM’s many accusations that everyone around him is a meth head. Cookers in the mountains or trade hubs or whatever. “secrets in the mountains”
* it seems like a lot to get into in 2 years, but maybe BM became involved in this crowd through the people he hired for his business. Or moved to CO after learning of the “opportunity” in IN. Or from the nephew.
* SM starts figuring it out and confronts him on Friday. BM panics decides she has to go.
* He hires one of his drug associates to do it, likely Sat morning. That is why he needed to be with MG that morning and why he cut the day short. Too much adrenaline.
* This associate takes her from the house (abducts) and kills her. Maybe it was even someone she knew though BM (maybe someone “known to her” did it). She is stored somewhere off property (a cooler?) until it is safe for nightfall.
* my assumption is that everything is a little sloppy because he was planning to get rid of her for a while, or had talked with this person about doing it, but something kicked the plan into gear sooner than he thought.
* Rest of Saturday is being seen in town and scrambling to set up Sunday. Things start going off the rails.
* he buries some evidence at the Salida site. Then he goes and buries her in the early morning. Possibly with the other person. (two people DID see her say day, but she was already dead)
* he needed the three contractors out of town Sunday in case they saw weird things missing at the office or if LE came by asking questions.
* plotting it is one thing, but Actually doing it is another. (per MG, he looked like he had had the worst night of his life)
* once he’s “safe” with his alibi, he starts the process of talking to the girls and the neighbor
* also explains LE’s handling of the case. Maybe they are trying to catch the Bigger Fish.
or maybe I’ve just watched too much Breaking Bad
MOO IMO etc