Updated

PHILADELPHIA -- The parents of a US student arrested in Cairo hired prominent Philadelphia attorney Theodore "Ted" Simon -- who previously represented Amanda Knox -- to help their son, WCAU reported.

Gregory Porter, 19, is one of three American students being detained on suspicion of throwing Molotov cocktails at security forces in the Egyptian capital.

Simon served as counsel for Seattle native Knox, who was convicted of murdering British student Meredith Kercher in Italy and subsequently acquitted on appeal.

Porter and his fellow students, all on a study abroad program, were arrested Monday night near Tahrir Square and could be seen in Egyptian state TV footage lined up against a wall by a table with several ID cards, including an Indiana driver's license.