Hopi tribal leaders and Arizona's members of Congress are asking U.S. law enforcement to stop the sale of about a dozen sacred Hopi artifacts at a Paris auction house in June. The Hopi Tribe contends the auction house is illegally selling the spiritual objects, known as Katsina Friends, and is urging U.S. Department of Justice and the FBI to help recover them. The items resemble masks and are used during religious ceremonies and dances to invoke ancestral spirits. They are communally owned, rarely displayed and never supposed to leave the reservation. This is the sixth time the French auction house, Estimations Ventes aux Encheres, has sold objects sacred to Native American tribes. It has argued that the items legally belong to collectors, and a Paris court has ruled that such sales are legal.