NIA deals with terrorism & such activities
The National Investigation Agency Act provides for creation of the National Investigation Agency (NIA) in the country.
The NIA Act was enacted in the aftermath of the Mumbai terrorist attacks of 2008. The enactment of NIA Act in fact was a course of action perilously close to crossing the constitutional limits because policing is a state subject under the Constitution. No central police force could be established except having the Central Bureau of Investigation (CBI) which is acting as a substitute for a national police force at times as police is not a union subject for law making. However there has been a plea for enacting a CBI Act for creating a national police force which did not go much forward.
NIA is the only federal agency in the country, along the lines of the Federal Bureau of Investigation (FBI) in the United States of America. NIA is much more powerful than the CBI though its resources and facilities are quite limited.