TORONTO -- U.S. Customs and Border Protection (CBP) officers seized a human brain in a Canadian mail shipment, according to a release.

CBP says officers examining a Canadian mail truck found a Canada Post shipment marked “Antique Teaching Specimen” and opened it on Feb. 14.

Inside they found “a human brain specimen inside of a clear glass mason jar without any paperwork or documentation in support of its lawful entry into the United States,” the release states.

The discovery was made at the Blue Water Bridge connecting Sarnia, Ont. to Port Huron, Mich.

According to CBP, the package originated in Toronto and was bound for Kenosha, Wisc. It added that its specialists are in contact with the U.S. Centers for Disease Control and Prevention to figure out what to do with the brain.

“Individuals looking to import shipments such as this, need to remember that the Center for Disease Control and Prevention has a strict import permit program that must be adhered to,” the CBP’s area port director Michael Fox said in a press release.