I have long thought SC killed Charli in Haiku. Now, though, I suspect he lured her under some pretext up the Hana Hwy, in her car after he removed the tell-tale grill, shot her in the face at or near that location, dragged her out, hastily covered/buried her, drove back to hide/burn the car, destroying any blood/tissue evidence and later(?) returning to more permanently dispose of the body(ies). I am thinking the clothing, etc. weren't planted but were likely left behind in haste or dropped due to clumsy efforts to dispose of the body. I haven't refreshed in my mind the timeline of known activities, so I'm not sure what day he returned. MOO. I do believe, though, that on 2/11 when he "helped the family search" (in the area where the clothes, etc. were eventually found) he was observed acting very protectively of that very road and that he went down it alone. MOO. Apparently Charli's sister searched there again probably because of SC's suspicious behavior and found the evidence. I have no idea what he did with the body once she was uncovered.
Feel free to correct my thinking.
Just found one hole: according to family, Charli's car was low on fuel. Any way around that?
Hole number two: How/why would he remove grill if Charli was alive in car with him? Going to revisit my original theory.