A person of interest was in custody Sunday after a college student was murdered and found dead in her car at a campus parking garage in Chicago, authorities said.

The person, who was not identified, was seen entering the garage shortly after Ruth George, 19, arrived there early Saturday morning, University of Illinois Police Chief Kevin Booker said in a statement.

Booker said the person is not affiliated with the university.

George, who was from the suburb of Berwyn, had entered the garage alone at 1:35 a.m., Booker said. After relatives told authorities that they hadn’t heard from her since Friday night, police tracked her cell phone to the structure, just south of downtown Chicago.

George's body was found in the back of a family car, Booker said.

The Cook County Medical Examiner's Office said Monday that George died of strangulation, declaring her death a homicide.

Booker said university police were continuing to investigate George’s death with local, state and federal authorities.

George, a kinesiology student, was a member of the university’s Honors College, chancellor Michael Amiridis said in a statement. He described her as a talented student who wanted to become a health professional.