Six skulls sent from the Netherlands seized in Chicago

Last month, U.S. Customs and Border Protection seized a suspicious shipment en route to the state of Iowa from the Netherlands. The packages proved to be six human skulls.

X-rays showed anomalies in a shipment at the Mail Facility in Chicago's O'Hare International Airport on March 29, according to a press release by U.S. Customs and Border Protection. The package contained two skulls swaddled in bubble wrap.

Two more packages from the same sender in the Netherlands also were found to hold two skulls each. The skulls were referred to the Centers for Disease Control and Prevention to be inspected further.

No information has been given about the sender. U.S. Customs and Border Protection considers the find one of the most "notable" of the past six months.