HARRY MARKOPOLOS, a former securities industry executive turned independent financial fraud investigator, was the whistleblower who provided credible and detailed evidence several times from 2000–2008 that should have prompted an immediate investigation by the United States Securities and Exchange Commission into Bernie Madoff's $65 billion Ponzi scheme. Markopolos's investigation was assisted by his investigative team, including Frank Casey, Neil Chelo, and Michael Ocrant. The retelling of their true story was assisted by David Fisher.