Originally created to address defective gunpowder in the Civil War, qui tam laws like the False Claims Act now underpin billion-dollar sanctions against multinational companies. These laws encourage individuals to report fraudulent activities, operating on the principle that it takes a “rogue to catch a rogue,” to expose wrongdoings effectively. Individuals involved in the fraud, including co-conspirators, can file claims and often serve as valuable resources in investigations. While immunity is not guaranteed for all informants and crime kingpins have never been rewarded, insiders play a crucial role in catching perpetrators. The substantial sanctions and the ever-present threat of whistleblowers contribute to the deterrence effect of the False Claims Act, making it a highly successful law at the federal, and sometimes state and city levels.