While the Central Intelligence Agency focuses on the gathering and analysis of foreign intelligence, the Federal Bureau of Investigation focuses on criminal law enforcement and protecting against terrorist and foreign intelligence activities. The CIA and the FBI are both agencies within the U.S. government and have some overlapping functions.
The CIA's primary mission is to gather foreign intelligence information, analyze and evaluate that information, and disseminate the intelligence to senior policymakers in the United States government, including the president. While the FBI also gathers intelligence, its primary mission is to thwart foreign intelligence activities and to enforce federal laws. The CIA is focused on foreign activities and does not act as a law enforcement body. The FBI focuses on crimes that are too large or complex for city, county or state law enforcement to handle, including high profile white-collar crime, public corruption at all levels of governance, civil rights issues, cyber crimes and terrorist activities.
The CIA can engage in covert action abroad when directed to do so by the president. The FBI can engage in special tactics and hostage rescue activities through their Special Weapons And Tactics teams and Hostage Rescue Team. The FBI also coordinates with local, state, international and partner agencies to provide support and leadership as requested.