In the first half of the episode, we fully believe Adora is the killer. She has the motive (her Munchausen boy proxy consumes her, just like Camille's obsession with writing words on her body), the means (Ann's body was found on her pig farm, and Alan (Henry Czerny) could have easily assisted his wife in the crimes), and she has the opportunity (she was close with both girls, and has an ample amount of medicine and poison to knock either one out). Her total lack of empathy towards her own blood (Camille) and lack of responsibility for Marian's death (she inadvertently confirms that she cremated Marian (Lulu Wilson) without telling anyone, thus covering up the fact that she accidentally killed her), indicate that she could kill two unruly teen girls and show little to no remorse. Once Adora is found out to be the type of mother who purposefully makes her children sick in order to have them need her ("See how nice it is not to fight?" she tells Camille as she vomits bile into a porcelain tin. Later when Camille's nearly lifeless body is floating in a tub, she whispers "I’ve waited for this for so long... for you to need me") it's easy to fill in the gaps. She didn't want Camille to talk about the case because she knew who did it. She wasn't that strict with Amma because she knew that the killer wasn't really out there. She was cozying up to Chief Vickery because she knew he'd never look into a woman he fancied — or a woman at all. But time reveals all secrets.