IOWA CITY — The 20-year-old leader of recent “Black Lives Matter” protests across Iowa City remained in police custody Monday after his arrest Sunday evening, as a judge determined she doesn’t have discretion to order his release from Department of Corrections custody. Mazin Mohamedali, a longtime Iowa City resident, has been in state custody since his 2018 arrest on suspicion of robbing a Kum & Go while displaying a knife, according to police.