Questions on Casey Anthony Trial?

Why put duct tape on AFTER decomposition? The tape slid off the face FROM decomposition. Who's to say she put the tape over both her nose and mouth? I think she OD'd her and taped her mouth shut. Then she "accidentally" died. She kept her body in the trunk because she didn't know what to do. It was too hard to bury her, which is why she borrowed the shovel, so she threw her in the woods. NO ONE goes as long as she did with Caylee missing unless they're really guilty.