Basics: CIA (Central Intelligence Agency) is the intelligence agency of USA meant for combatting external threat. FBI (Federal Bureau of Investigation) is the one which is responsible for combating internal threat. MI5 (Military intelligence 5) works for UK the same way the CIA works. MI6 works the way FBI works. IB (Intelligence Bureau) is India's intelligence agency which keeps and eye on internal threat. RAW (Research and Analysis Wing) is India's intelligency agency taking care of external threat. CBI (Central Bureau of Investigation) is the criminal investigation body of India. NIA (National Intelligence Agency) is a federal agency to combat terror in India. Story goes like this: Before 9/11 United States CIA had Counter Terrorism Center (CTC) for terrorist threat. It was actually meant for external threat. On the same ground, Bajpayee Govt. formed CTC under an executive order as a part of IB and named it Multi Agency Center (MAC). As IB its