The agency took over the case from Punjab Police following a Home Ministry order on Thursday, nearly a month after the state government decided to hand over the investigation to it.
Gosain, 60, was returning home after attending a morning drill (RSS Shakha) when he was attacked by two unidentified bike-borne assailants in Ludhiana last month. He died on the spot while the attackers fled.
Punjab Chief Minister Captain Amarinder Singh had decided to hand over the probe to the NIA while announcing Rs 5 lakh compensation for the deceased’s family and a government job for one of his progeny.
The NIA, in compliance of the Ministry of Home Affairs order, has re-registered the case under sections 10, 12 and 13 of the Unlawful Activities (Prevention) Act, sections 302 and 34 of the Indian Penal Code and section 25 of the Arms Act at Jodhewal police station yesterday, the spokesman said.
An NIA team from New Delhi has reached Ludhiana to take over the investigation.
On October 17, two unidentified persons killed Gosain, chief of Raghunathnagar Shakha of the RSS in Ludhiana, when he was sitting outside his house.
Initially, a three-member Special Investigation Team (SIT) led by Deputy Commissioner of Police Gagan Ajit Singh was formed by the state government to probe the case.
Gosain, who lost his wife to cancer some years ago, is survived by four children.
The killing of the RSS leader was the latest in a series of murderous attacks on right-wing and religious leaders in Punjab. This was the eighth such incident in the state since 2016.