Sharp Objects Ending Explained
2. Who Framed John?
The key suspect in the killings initially is John Keane, the sister of murder victim Natalie, who's fingered by the town because he cries too much over the death of his sister. Both the audience and Camille know he probably isn't responsible, but the evidence is admittedly against him.
First up is the fact that Ann's bike is found buried in pig manure, an object which a witness claims John put there himself. The second is Natalie's blood, found in the bedroom John has been staying in since returning home.
The validity of the bike is questioned from the get-go, with the worker who claimed he saw it being disposed of at midnight only ever having shifts during the day. It was most likely Amma herself who buried the bike and bribed the worker, as she's seen on the premises and talking to an employee early in the show.
It's never made clear if the witness was the same person, but it would make sense. That doesn't rule out Adora, though, who could have had a hand in it as well. After all, it was found on her land by one of her workers while she was there.
The second piece of evidence, however, is purely accidental. Amma and her roller-buddies killed Natalie in that room, a room which Ashley confirms all the girls used to play in. Natalie was killed there, unbeknownst to John.