It is interesting that in one statement officials state that they don't believe the ranch hand to be involved despite being brother to the two arrested suspects and then later it is amended that they don't have any evidence linking him to the crime. See posts 242 and 243. Is this just different wording to say the same thing or are they growing suspicious of Noel?
It'll be interesting to see how this unfolds, but I'm not going to lie, IMO, it would seem likely that the ranch hand, despite being shot, may have had some involvement. On the other hand, the two brothers may have come up with the plan based on their brother innocently talking about the comings and goings of the Doctor or what valuables were at the ranch. We shall see.
Peace be with the Doctor's family and all that cared for him, it appears he was a special being who was lost way too soon.