In the late 1990s and early 2000s, Manhattan’s Knoedler Gallery made about $80 million selling art by Mark Rothko, Jackson Pollock, Robert Motherwell, and other Abstract Expressionist icons. But in 2011, the truth came out: the paintings were forgeries. The buyers were scammed. Employees at the Knoedler claimed they, too, were victims. But were they actually in on the criminal conspiracy?