Dr. Christos Tsirogiannis is an associate professor at the Aarhus Institute of Advanced Studies and head of the working group Illicit Antiquities Trafficking of the Unesco chair on threats to cultural heritage and cultural heritage-related activities, Ionian University, Greece, focusing on antiquities and trafficking networks. Prof Christos Tsirogiannis, informed the competend US authorities and urged Hindman Auctions in Chicago directly and through Guardian to cancel its auction of the portrait head of Antisthenes, the Greek philosopher, scheduled for Thursday. The available photographic evidence of the head directly linking the transaction to a dealer involved with illicit trade.