One question looms large over the trial in Germany of two ex-Volkswagen ( VOWG.DE ) managers in a sex-and-bribery scandal: "What did VW Supervisory Board Chairman Ferdinand Piëch know, and when did he know it?" It has been two years since an internal sting showed Volkswagen managers funneled $2.9 million in secret payments to VW's once-powerful former labor boss and supervisory board member Klaus Volkert. The investigation revealed that works council leader Volkert used the bonus payments to finance "pleasure trips" including parties and prostitutes for himself and other VW labor representatives—news that shocked Germany. But as Volkert's trial got underway Nov. 22, new revelations raised questions about Piëch's knowledge of the affair.