One of the sons of Muslim Brotherhood General Guide Mohamed Badie was killed on Friday in Cairo during "Day of Rage" protests against the army-backed government, the Brotherhood's Freedom and Justice Party said on its Facebook page.Ammar Badie, 38, died of a bullet wound sustained while taking part in protests in Ramses Square on Friday, it said. Badie's whereabouts are unknown. He has been charged with inciting violence and faces a trial that starts on Aug. 25.