I'm pretty sure there is the potential that a report of sexual assault could be made to the school and they begin Title IX investigations internally. Meanwhile the police department investigates and either declines to charge or the individual refuses to press charges after the initial report (happens a lot). So, the school could continue their investigation and determine a Title IX violation occurred or likely occurred and report that to Frost who decides to suspend the players.
Mo's case occurred before he was student and does not not include a student of UNL. So, I don't believe the school could or would investigate it independently as a Title IX violation and thus is waiting for the legal scenario to play out to determine punishment.