The Federal Bureau of Investigation (FBI) is the primary investigative arm of the United States Department of Justice (DOJ), serving as both a federal criminal investigative body and a domestic intelligence agency. At present, the FBI has investigative jurisdiction over violations of more than 200 categories of federal crimes, making the FBI the de-facto lead law enforcement agency of the United States government. The motto of the bureau is "Fidelity, Bravery, Integrity."

The FBI headquarters is in Washington, D.C., and there are also 56 field offices located in major cities throughout the United States as well as over 400 resident agencies in smaller cities and towns across the nation, and more than 50 international offices, called "Legal Attachés," in U.S. embassies worldwide.

Mission and priorities

In fiscal year 2006, the FBI's total budget was approximately $8.7 billion, including $495 million in program increases to enhance counter-terrorism, counter-intelligence, cybercrime, information technology, security, forensics, training, and criminal programs. According to its congressional budget justification for the fiscal year 2009, for the past several years the FBI has assumed a growing responsibility for collecting foreign intelligence, in response to a May, 2006 request from the Director of National Intelligence.

It was established in 1908 as the Bureau of Investigation (BOI), and the name was changed to the Federal Bureau of Investigation (FBI), in 1935.

The mission of the FBI is "To protect and defend the United States against terrorist and foreign intelligence threats, to uphold and enforce the criminal laws of the United States, and to provide leadership and criminal justice services to federal, state, municipal, and international agencies and partners."

Currently, the FBI's top investigative priorities are:

1. Protect the United States from terrorist attack (see counter-terrorism);
2. Protect the United States against foreign intelligence operations and espionage (see counter-intelligence);
3. Protect the United States against cyber-based attacks and high-technology crimes (see cyber-warfare);
4. Combat public corruption at all levels;
5. Protect civil rights;
6. Combat transnational/national criminal organizations and enterprises (see organized crime);
7. Combat major white-collar crime;
8. Combat significant violent crime;
9. Upgrade technology for successful performance of the FBI's mission.

In August 2007, the top categories of lead criminal charges resulting from FBI investigations were:

1. Bank robbery and incidental crimes (107 charges)
2. Drugs (104 charges)
3. Attempt and conspiracy (81 charges)
4. Material involving sexual exploitation of minors (53 charges)
5. Mail fraud - frauds and swindles (51 charges)
6. Bank fraud (31 charges)
7. Prohibition of illegal gambling businesses (22 charges)
8. Fraud by wire, radio, or television (20 charges)
9. Hobbs Act (17 charges)
10. Racketeer Influenced and Corrupt Organizations Act (RICO)-prohibited activities (17 charges)