CAIRO (Reuters) - An Egyptian court on Monday acquitted Irish citizen Ibrahim Halawa and his three sisters of charges including murder in a mass trial that has been going on for over four years, during which he was in jail. Halawa was part of a trial in which nearly 500 people were charged with, among other crimes, breaking into a mosque, killing 44 people, including a policeman, and illegal possession of firearms in violence that followed the military s ouster of former Islamist president Mohamed Mursi in 2013. 