An Arkansas coroner was investigating after a cargo shipment of 40 to 60 human heads was discovered by a Southwest Airlines employee, NBC DFW reported Thursday.
The container of heads was found in Little Rock, Ark., last Wednesday and was set for transportation to a Medtronic research lab in Fort Worth, Texas.
"It wasn't labeled or packaged properly," Ashley Rogers, a Southwest spokeswoman, told NBC DFW. "They called the local authorities."
Police were called by the airline, who investigated before turning them over to the county coroner.
A spokesman for Medtronic told NBC DFW it was common practice to ship body parts for medical education and research, adding his firm expected suppliers to follow proper procedures.
Pulaski County Coroner Garland Camper, charged with the investigation, said he was waiting for the correct documentation to prove the heads were for medical research before releasing them.
"In our discussion with the health department, we've come to the conclusion that there is a black market for body parts out there," he was quoted as saying by NBC.
"We just want to make sure these specimens aren't part of that underground trade."