CHICAGO (AP) — The death of a University of Illinois at Chicago undergraduate student whose body was found inside a campus parking garage has been ruled a homicide

The Cook County medical examiner says Sunday’s autopsy showed 19-year-old Ruth George of Berwyn died of strangulation.

UIC police Chief Kevin Booker said Sunday that a person of interest was in police custody and the suspect has no affiliation with the Chicago school.

Campus police found George unresponsive in the garage on Saturday after her family had reported her missing. Chicago authorities pronounced George dead at the scene.

School officials said in a letter circulated to students that campus police are working with city and federal law enforcement agencies in the investigation.