From other news reports, the stepmother says she was not murdered but out of fear and confusion, her husband "did something horrible". Apparently she was abusive to the little girl but didn't cause her death. If that is either so or the prosecutor can not prove otherwise, you are left with with abuse of a corpse which is usually a misdemeanor or low level felony.
God grant me
The Serenity to accept the things I cannot change,
The Courage to change the things I can,
And the Wisdom to know the difference.