Investigators are attempting to locate a 19-year-old University of Illinois student who vanished from Chicago’s O’Hare International Airport shortly after checking in for a flight, family members said.

Hye Min Choi, a 19-year-old student at the University of Illinois, has been missing since Saturday evening. Choi vanished after checking in his luggage for a scheduled flight at the Chicago O’Hare International Airport.

Police officials said that the missing student, who is also referred to as Joseph, was supposed to board a United Airlines flight 5892 home to Greensboro, North Carolina. Choi’s luggage arrived at the intended destination without him. United Airlines’ records reveal that he didn’t re-book a flight.

“There doesn’t appear to be any criminality involved. The young man was apparently having some problems in school,” police superintendent Garry McCarthy said. “We have some leads on where he might be. It appears that he might or might not have wanted to go home,” abc7chicago reports.

Choi is described as 5.6 feet, with brown eyes, black hair and a medium complexion. He weighs 100 pounds and has a scar on his right eyelid, Huffington Post reports.

Choi’s family said that they had a chat with their son at 4:50 p.m. two hours before his flight. During the conversation, Choi told his family that he was “hungry,” NY Daily News reports. Credit card records showed that the missing student made a purchase at a McDonald’s store at the airport, about 40 minutes before his departure.

The family also said that their son cannot drive; hence Choi had no reason to leave the airport.

Choi’s sister, Catherine Choi, said that her brother deliberately missing his flight home is “completely and totally out of character. He doesn’t have the character of someone who would decide not to get on the flight and not contact his family,” abcnews reports.