Rozan, 10, was rushed to hospital with head injuries and doctors had raced against time to save her life.
Her father and his wife had claimed she could have been poisoned by food and fell on the ground but forensic tests showed she had died of brain haemorrhage due to a blow by a sharp object.
“Tests showed there were glass shreds on her head…police discovered later that the girl had been hit by her step mother by a bottle of chilli sauce,” Sabq newspaper said in a report from the western town of Makkah.
It said examination also showed the girl had been subject to systematic torture at home as her body was covered with bruises.
Lawyers for the girl said they would ask court to strip the father of his custody of three younger children because of his negligence and failure to protect them, adding that they should be handed to their grandmother.