To suggest another scenario as to RG’s work, and this is simply a guess. What if the 50k was a barter situation? The basement had been flooded by busted pipes over the winter, all the drywall, woodwork, etc. had to be replaced and painted. RG did or was going to do the work in exchange for rent, board, lessons and training for 4 or 5 horses for x amount of time. LK felt that the agreement was that MB would be the trainer/instructor, but MB put her off on the assistant instructor. LK resented that and felt it wasn’t a fair exchange. They had words about it, resentment growing on both sides. Then everything came to a boiling point with disagreements and ridiculousness from both sides and everything got completely out of hand in just a few days. LK needed to move but there was the issue of work and materials already furnished by RG that MB needed to reimburse if they were leaving the farm. Then more disagreements over the amount, etc. MB had made an insurance claim based on RG’s work estimate, he received the insurance check, then things fell apart. MB wanted them out but refused to pay for any of the work in lieu of the original barter agreement. Both parties consulted attorneys to figure out a settlement, MB wanted them to sign a new agreement for partial reimbursement (the papers he was insisting they sign), LK and RG didn’t think that was a fair amount and wouldn’t sign, more drama ensued. MB couldn’t contain his impatience and temper. Insults and accusations were flying from all parties. If the basement had living quarters with no emergency outside egress, I could see that being in violation of code and no one would be allowed to live down there, not that the work was subpar. That doesn’t explain all the other drama, and certainly no excuse for MB to shoot anyone no matter how tense the situation. Nor any excuse to even take a gun to threaten them. If he felt he needed a gun for self defense, then he shouldn’t have driven down to the house. Poor communication and negotiating skills from all parties that lead to the final outcome. Again, had the gun not been involved, it would have simply been a messy barn drama that few people would ever had heard about.
If MB used to have several guns, and he was having financial problems, it’s plausible that he sold his guns and that’s why he ended up using RC’s gun, instead of his own, to shoot them.