Inspector General Michael E. Horowitz admitted in the 77-page report that the agency could not point to a single major terrorism plot thwarted as a result of the vast expansion of federal spying authority granted in the bill. Horowitz said that between 2004 and 2009, the period when the FBI tripled its use of bulk metadata collection under Section 215 of the Patriot Act, compelling businesses to turn over records and documents on Americans led to a bloated system that revealed no ties to official terrorism investigations.