I think that they'll solve it. If they didn't want to solve it, for any reason at all, then they could have easily called this familial, in that KR went off the deep end, murdered them all over being pushed out of the weed op, then killed himself with a single gunshot wound to the head. DS could be made to go along with that, and the autopsies would still be sealed, due to the drugs involved and the investigation of further activity as a result of the murders. They didn't even have to tell us about the weed. They could have just said; Illegal drug activities were going on at three sites, with a street value of half a million dollars. It seems KR and his family had a falling out...yada yada yada, he murdered them and killed himself. That would be plausible. Look up how many times a single, white, male, does that.
Edit:
In fact, I've often thought, if that's not what they tried to make it look like, when they killed KR. A major family falling out, and KR was the perpetrator, instead of the traitor(s) who did it.