Ronald Hendricks, judge president of the North West high court, and Neo Morei, an acting judge, agreed with Mosiane that the court that tried him was not properly constituted and then freed him in May, just over a year into his life sentence.
The appeal is upheld. The conviction and sentence are set aside, the judges said in their judgment.
Winnie said the courts decision to free Motlodi has shattered the family.
There is no closure for us there was an injustice. We will not be doing anything because nothing will bring my daughter back, she said.
Dr Llewellyn Curlewis, a former prosecutor and advocate who is a senior lecturer in the law faculty at the University of Pretoria, said assessors help in determining the accuseds fitness to stand trial and assist the judicial officer in understanding the facts of the case.