Denver police are investigating the theft of a box containing human heads from a parked freight company truck, officials said Saturday.
The box was being transported for medical research purposes, police said in an email.
Someone broke into the truck while it was parked between Wednesday afternoon and Thursday morning, NBC affiliate KUSA reported.
The blue-and-white box was marked with a label that said “Exempt Human Specimen,” police said. A dolly was also stolen from the truck.
No arrests had been made as of Saturday and investigators asked anyone who finds the box to call police.