A woman died at O'Hare on Thursday morning, according to Chicago officials.
The Chicago Fire Department was called to O'Hare around 7:45 a.m. to reports of a woman "pinned in machinery" at the Terminal 5 baggage area.
The woman was entangled in the conveyer belt system used to move baggage, the fire department said. She was pronounced dead at the scene.
Chicago police said the woman, who did not work at the airport, was seen on video going into a restricted area that was unoccupied around 2:30 a.m. Her body was found hours later.
Police confirmed the woman was apparently at the airport overnight, but it remains a mystery why she snuck into the employees-only area.
Authorities said the area where the incident happened is restricted to employee access, and while considered secure, it is not considered a high security area. It is filled with conveyor belts bringing luggage to and from airplanes in the international terminal, which also go through customs inspection.
While the woman's age was initially reported to be in her 40s, police clarified she was 57 years old. Her name has not been released.
Police have not said whether they have been able to track the woman's activities between 2:30 a.m. and 7:30 a.m.
Chopper 7 was over the scene around 9 a.m. showing a large presence of first responders.
Chicago police are investigating her death. The Cook County medical examiner's office has not yet released the identity of the woman who was killed. It's unclear where she lived or why she was at the airport.