Attorneys for the man accused of killing Mollie Tibbetts last year want the court to allow expert witnesses to testify.  A motion was filed Wednesday (10/16) in Poweshiek County to let an expert in sleep deprivation testify on behalf of Cristhian Bahena Rivera.  Bahena Rivera is accused of killing Tibbetts in July of last year in Brooklyn.  The defense contends Bahena Rivera’s confession to police should not be used as evidence in his trial, which is scheduled for February 4 in Sioux City.