The Chicago Tribune reported Tuesday the shipment arrived in late December but the paperwork was incomplete and it was unclear where it was supposed to go.
News stories surrounding the shipment Tuesday prompted a suburban company to notify authorities it was the intended recipient.
The heads had been embalmed and had been used for medical research, a spokesman for the Cook County medical examiner's office said. They had been shipped from Rome aboard Lufthansa.
It wasn't clear why the heads were transported halfway around the world to be cremated.
The medical examiner's office had been holding the heads for safekeeping since the week before Christmas.