VALPARAISO, Ind. (AP) — Operations have returned to normal at Valparaiso University, and authorities are questioning a person of interest in connection with an earlier report of a potential hostage situation on campus.

Valparaiso spokeswoman Nicole Niemi says students were ordered to “shelter in place” Tuesday night after the Porter County Sheriff’s Department received a phone call indicating there was a potential hostage situation in the university’s Christopher Center for Library and Information Services. Police were dispatched and the library sealed to prevent access.

An initial sweep of the building didn’t turn up any evidence of a hostage situation or a shooting.

Niemi says the sheriff’s department is questioning a person of interested related to the phone call.

The Christopher Center will reopen Wednesday. All classes and other events will occur as scheduled.