The probe agency led by Inspector General G P Singh also visited the crime spot where Gosain was killed, a police official said here.
The RSS leader was shot dead on October 17 by two motorcycle-borne persons near his house in Gaganjit colony.
Later, the Punjab government handed over the probe to the NIA.
This month, the state police had claimed to have achieved a major success in solving several targeted killing cases including that of Gosain with the arrest of five persons.
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The arrested included Jimmy Singh, Jagtar Singh Jaggi, shooters Hardeep Singh Shera and Ramandeep Singh.
Jimmy was produced in a local court in another case and was remanded to one-day police custody.
Commissioner of Police R N Dhoke said that a police team left for Moga to bring Ramandeep and Shera here for further investigation.