Internal Revenue Service, Criminal Investigation ( IRS-CI ) investigates potential criminal violations of the U.S. Internal Revenue Code and related financial crimes in a manner intended to foster confidence in the tax system and deter violations of tax law. While other federal agencies [ which? ] also have investigative jurisdiction for money laundering and some bank secrecy act violations, the Internal Revenue Service (IRS) is the only federal agency that can investigate potential criminal violations of the Internal Revenue Code.
John Dennis Hastert ( / ˈ h æ s t ər t / ; born January 2, 1942) is a former American politician who served as the 51st Speaker of the United States House of Representatives from 1999 to 2007, representing Illinois's 14th congressional district from 1987 to 2007.  He was the longest-serving Republican Speaker of the House in history, and is currently the highest-ranking holder of a political office in U.S. history to have served a prison sentence.