My husband has a decent theory about what happened. He thinks Casey took Caylee to the babysitter just like she said she did. He thinks that when she went to pick Caylee up, Caylee was gone and the babysitter and Casey got into a fight, which resulted in the babysitter ending up dead. He thinks Casey acted in self defense. The babysitter may have sold Caylee and was lieing, saying she was kidnapped by very bad people, don't go to LE, etc.
He thinks the babysitter corpse is what was in the trunk and what the dogs hit on. I asked him how Casey could have moved the body of a grown woman alone and he said, maybe she wasn't alone when she went to pick Caylee up.