The director of the Board of Antiquities said the piece was found in Shahat during excavating work in 1973 and disappeared in 1999.I wonder if the report is a little confused and has lost detail in translation. I know of no auction house called "Athens Hall". But I presume this is an antiquities dealer with branches in New York and London.
Search led to the piece being in the possession of Athens Hall Auction House owned by an American with branches in London and New York.
It was disclosed that the piece was acquired by the Hall in June from a antiquities trader in Zurich, Switzerland.
Shahat is otherwise known as Cyrene, so it is safe to presume that this theft is linked to material from the site (Mark Rose, "Stolen Sculptures from Cyrene, Libya", Archaeology, January 30, 2001).
Alerted of the theft by Emanuela Fabbricotti of the Italian Mission to Cyrene, White and Kane created a website, www.cyrenethefts.org, on which they posted information about the loss his January 22. Two heads--one of a male and the other possibly of Demeter--were relocated within as many days of the appearance of the website, thanks, says White, "to the energetic interventions of Jean-David Cahn, president of the International Association of Ancient Art Dealers, and Jerome M. Eisenberg, director of the Royal-Athena Galleries." The case highlights the potential of the web in publicizing the theft of antiquities and helping in the recovery of stolen artifacts.The website is no longer functioning.
Donald White issued this statement back in 2001 [archived]:
In 1969 an international team of investigators began excavating the Extramural Sanctuary of Demeter and Persephone at Cyrene in the province of Cyrenaica of what is today eastern Libya. The project was begun under the sponsorship of the University of Michigan's Kelsey Museum and was taken over in 1973 by the University of Pennsylvania Museum of Archaeology and Anthropology. Fieldwork ceased in 1981 after nine seasons of activity directed by Penn's Dr. Donald White, largely because of the deteriorating relations between the governments of Libya and the United States. During the years between 1969 and 1981 a very substantial quantity of stone sculpture was unearthed from the sanctuary's ground. Professor Susan Kane at Oberlin is the principal investigator responsible for the publication of this material. It now our sad duty to report that a major theft of this material was carried out some time in late 1999 or early in 2000. A gang of persons as yet largely unidentified broke into the University of Pennsylvania's storerooms through a broken window and removed what appears to have been a total of 15 marble heads. These objects represent some of the most interesting and archaeologically valuable artifacts found by us in the course of the entire excavation. A list of the stolen pieces was provided to us by Professor Emanuela Fabbricotti of the Italian Mission to Cyrene in November 2000. While the current location of the stolen pieces is still a matter of speculation, it is likely that they were transported across the border into Egypt fairly soon after the initial theft. None of the principals responsible for the thefts have been apprehended by the Libyan authorities, and many details surrounding this event remain obscure owing to the on-going absence of direct communications between us and the Libyan Department of Antiquities headquartered in Tripoli. Fortunately we possess a complete documentation of all of the pieces reportedly lost. In the meantime we appeal to the public at large as well as to all of our scholarly colleagues to report to us any information they might have about the missing pieces.