The eerie mystery of why more than a dozen human heads were sent to Chicago's O'Hare International Airport is now solved.
The 18 human heads were discovered during routine x-ray screenings a week before Christmas.
Airport employees found the heads stored in formaldehyde in three sealed containers.
U.S. Customs seized the cargo because it was missing paperwork.
But on Wednesday, the Cook County Medical Examiner received the heads. A spokeswoman for the medical examiner's office says the heads were originally sent to a medical research facility in Rome. The heads were then scheduled to return to Illinois to be cremated as part of the agreement.
Paul Dudek, of the Anatomical Gift Association of Illinois, says the shipping of body parts or cadavers is more common than one might think.
"Last week, we did send out 10 brains to the University of Texas in Austin," Dudek said.
Dudek believes the embalmed heads may have been used for dental or medical training.
You watch the story in the video above.