This case details the in-house discovery of WorldCom's fraudulent accounting practices and the ethical considerations employees faced during the investigation. In May 2002, Cynthia Cooper, vice president of internal audit for WorldCom, the second-largest telecommunications company in the United States, faced an extremely difficult decision. After months of sleuthing, initially not sure what they were seeking, she and two of her employees at the Clinton, Mississippi, WorldCom headquarters had discovered almost $4 billion in questionable accounting entries. The specter of the Enron collapse in the fall of 2001 still loomed large, and Cooper realized that the situation at WorldCom might even be a far greater financial debacle. If this fraud were revealed, much would be at stake: the company's credibility, the fate of thousands of employees, and pension funds loaded with WorldCom stock.