But on Wednesday prosecutors were successful in their own appeal to the High Court.
In a 3-2 split decision, the judges found the Court of Appeal made an error in reducing the sentence and ordered the case be returned to that court for Guode to be re-sentenced.
Guode had survived rape and her soldier husband’s death in war-torn Sudan before coming to Australia as a refugee.
She pleaded guilty to murder over the death of her twins and to infanticide over the death of her youngest child.
Infanticide carries a shorter maximum prison sentence and takes into account that “the balance of [Guode’s] mind was disturbed” because of the birth of a child two years before.
The High Court ruled the Court of Appeal made an error in considering her plea of guilty to that charge, and her relevant mental state, when sentencing her for the murder and attempted murder charges.
Guode was affected by a depressive disorder at the time of the killings.
She probably had the same mental state in relation to killing Bol as to her other children, three judges found.