That's usually the kind of crime only one person would commit. Its difficult to get a group of others to go along with planning and executing a more detailed massacre of 8 family members in 4 locations. Rhodens just didn't have the power or money to generate that kind of ill will with so many people, not enough to risk getting killed or sent to prison for life.
Rhodens may have angered someone who wanted personal revenge, but they probably were also a threat to others in a powerful criminal enterprise that had a great deal to lose (like people involved in drug trafficking and/or other criminal ring) The mass killing was to eliminate a threat and send a very powerful message to others "in the know" to cease operations or keep their mouths shut. That message could have applied to anyone in southern Ohio and KY, too.
The smart thing for LE to do would have been to offer protection to those locals who they thought might know the killers. LE made a deliberate, very public choice to NOT protect those witnesses who could have helped them. JMO, that means LE didn't want witnesses to talk, with some members LE possibly involved in the massacre themselves.
One scenario (among many) I've considered is a variation on the theme of competition between warring criminal factions in the region. Is it possible that a criminal enterprise that had cooperation or participation from local LE was trying to eliminate competition from another gang that wasn't linked to LE?
BBM - I agree.
If they walked all over more than one member, or a beloved member, of the same family, then there'd be more than one who'd come after them.
I just do not see the Rs as a threat to any big drug lord, based on what we have to go on. All we have to go on, is that they had a couple of grows, with, at most, a couple hundred plants (we've no proof of even that many). Between CR1, and KR, that would be a
possible gross of $39k if they sold by the pound, and, if it was pretty decent weed. Add a possible cut for GR for helping with labor, (approx 1 hour per day or or so for every 4-6 plants), no plant loss due to insects, mold, etc..., and other overhead such as electricity, nutrients, water, for example, and you've whittled that down a bit. Weed becoming legal would even lessen their income. Weed prices in legal states are dropping like rocks. Weed, in shops, in CO, are as cheap, or cheaper, than weed in illegal states, so you know that the growers, like the Rs, are taking a hit. (Like bootleggers here. My friend was a bootlegger (may he r.i.p.). He lost a pretty good bit of side income when the city went wet. I think he still had some late night Sat., and Sunday, customers but that was about it.) If the Rs were a threat to any big drug lord, they'd have likely just cut the head(s) off the snake, and in such a way that the others knew to keep their mouths shut, and close up shop.
If LE was mixed in somehow and thought they may be exposed, it's possible they may have taken it upon themselves, to eradicate any threat that could come back to bite them. Self-preservation.
I think it is something else though. I've considered that they (CR1 and maybe KR or GR) may have been blackmailing someone, and they didn't realize the individual(s) had the capacity to hit back with such deadly force.