Arrest of New York dealer

The New York Times is reporting continuing fall-out over the antiquities from Asia case (Tom Mashberg, "Prominent Antiquities Dealer Accused of Selling Stolen Artifacts", New York Times December 21, 2016). The case relates to Nancy Wiener.

The complaint states:

“Defendant used a laundering process that included restoration services to hide damage from illegal excavations, straw purchases at auction houses to create sham ownership histories, and the creation of false provenance to predate international laws of patrimony prohibiting the exportation of looted antiquities,”

Such claims undermine the position of the market at a time when dealers are claiming to conduct due diligence. How common is the creation of "sham ownership histories"? What about placing objects in collections so that they pre-date the 1970 UNESCO Convention?

Jason Felch adds an important observation:

“Even after a decade of reforms, the art market continues to be pervaded with stolen and looted antiquities.”