University of Colorado, Denver Police Chief Douglas Abraham said that the call alerted authorities to the presence of the unopened package in the campus mail room. He made the disclosure in a hearing in which defense attorneys were trying to determine who told Fox News that the package contained a notebook with writing that detailed violent plans.
Holmes' attorneys contend the disclosure violated a gag order.
Abraham and two other law enforcement officials said they didn't discuss the package with members of the media. They said it did contain a notebook and burnt U.S. currency.
Holmes sat silently during the hearing, sporting a full beard. It was first court appearance since being taken to the hospital for undisclosed reasons last month. The hearing was re-scheduled because of the incident. Several Denver media outlets reported that the hospitalization was due to the suspect banging his head against the wall of his jail cell.
Holmes is charged with killing 12 people and injuring 58 others during a shooting at a midnight screening of "The Dark Knight Rises" in July.