When I first heard this story, I felt Caylee died in the custody of Casey and she stayed away from her parents for 5 weeks to avoid having to tell them of the tragedy.
Now, with the Father's Day tape coming out where Cindy had seen Caylee on June 15, but Cindy stating before that the last day she had seen Caylee was June 9, and the lawyer stating that Casey can't state who has Caylee because Casey needs to save that for her defense, maybe Cindy was the one who had Caylee when she died. Or, Cindy and Casey both know exactly how Caylee died. The other thing to keep in consideration is Casey borrowing the shovel while her parents are gone. I think Caylee had been buried at the parent's place initially and Casey moved the body when she borrowed the shovel. She then disposed of the body again. This would explain why the cadaver dog hit at the parents' yard and also the car. Remember, they found hair, dirt and a stain in the car trunk. The hair would probably come lose pretty easily after decomposition sets in. Then, Casey abandons the car at the parking lot. (Did Cindy instruct her to plant the car somewhere it could be stolen, but it wasn't and instead impounded?)
I am beginning to believe Cindy sounds and acts like Susan Smith did in the first few days after she killed he sons. It really makes more and more sense that Casey and Cindy both know exactly what happened to Caylee.