There are repercussions for a small child dying in her mother's care-- it is manslaughter if the mother was culpably negligent. The problem is that like any other crime the State has to prove the culpable negligence beyond a reasonable doubt. They chose to put on a case for Murder 1, not for manslaughter, thus they did nothing to prove that she was negligent. That was the defenses theory, but without the State putting on evidence to prove that negligence you can't convict on manslaughter.
Again, this never should have been Murder 1. The State should have settled on a charge they could win with the evidence they had available, not grasp for straws with a murder 1 charge.
Dude. Lying about it and trying to cover it up for 30 days is culpably negligent imo.
Its really simple. You (Casey) tried like hell to hide it so you get manslaughter. And thats getting off easy.