Radical preacher Amritpal Singh's uncle Harjit Singh was brought to Assam by the Punjab Police on Tuesday morning, a senior official said.
Harjit Singh, who was moved to the Dibrugarh jail by road from Guwahati, is the fifth person linked to Amritpal's 'Waris Punjab De' (WPD) to be brought to the Northeastern state, he said.
A cavalcade of seven security vehicles took Harjit Singh from the Guwahati airport to the Dibrugarh central jail where he was lodged at 7.10 am, the official said.
He gave himself up before the police in the early hours of Monday.
Harjit Singh, who officials say helped his nephew gain control over the accounts of WPD, is among the five people slapped with the National Security Act (NSA), which allows the preventive detention of anyone who could threaten national security or public order.
On Sunday, four WPD members were brought to the Dibrugarh central jail after the Punjab government on Saturday began a major crackdown on the outfit, headed by Khalistan sympathiser Amritpal, who is wanted in several criminal cases. They are Daljit Singh Kalsi, Bhagwant Singh, Gurmeet Singh and 'Pradhanmantri' Bajeka.
Over 100 people have been arrested so far in the crackdown, according to Punjab Police.
Heavy security has been deployed at the Mohanbari airport in Dibrugarh, fuelling speculation that more WPD members could be brought to the BJP-ruled state from Punjab, around 2,500 km away.
Harjit Singh along with driver Harpreet Singh surrendered before the police near Bullandpur gurdwara in Jalandhar's Mehatpur area. Punjab's Deputy Inspector General of Police (Border Range) Narinder Bhargav was among the officers at the spot.
In a video shot then, Harjit Singh was seen producing his licensed 32-bore pistol and cash amounting to Rs 1-1.25 lakh that he was carrying in a Mercedes. The car was later seized and the two men taken away by the Amritsar Rural police, officials said.
Assam's Inspector General of Police (Law and Order) Prashanta Bhuyan reviewed the security arrangements in Dibrugarh on Monday.
Bhuyan refused to share details, stating, "These are sensitive matters related to the internal security of the state."
The Punjab Police crackdown on WPD began weeks after Amritpal and his supporters stormed the Ajnala police station near Amritsar to secure the release of an arrested associate.
The episode had raised fears over the possibility of the return of Khalistani militancy to the state that borders Pakistan.
WPD was formed by singer-activist Deep Sandhu. Amritpal took over as its chief a month after his death last year.