What happens when those who should look into the crime are the ones COMMITTING IT?!?!?

Overview 
The Bureau’s Public Corruption program focuses on:

Investigating violations of federal law by public officials at the federal, state, and local levels of government;
Overseeing the nationwide investigation of allegations of fraud related to federal government procurement, contracts, and federally funded programs;
Combating the threat of public corruption along the nation’s borders and points of entry in order to decrease the country’s vulnerability to drug and weapons trafficking, alien smuggling, espionage, and terrorism.
Addressing environmental crime, election fraud, and matters concerning the federal government procurement, contracts, and federally funded programs.
In 2008, the FBI created the International Corruption Unit (ICU) to oversee the increasing number of investigations involving global fraud against the U.S. government and the corruption of federal public officials outside of the continental U.S. involving U.S. funds, persons, businesses, etc. The ICU’s tasks include:

Overseeing the Bureau’s Foreign Corrupt Practices Act (FCPA) and antitrust cases;
Maintaining operational oversight of several International Contract Corruption Task Forces, which investigate and prosecute individuals and firms engaged in bribery, illegal gratuities, contract extortion, bid rigging, collusion, conflicts of interest, product substitution, items and/or services invoiced without delivery, theft, diversion of goods, and individual and corporate conspiracies on every level of U.S. government operations.