Pappalpreet is also alleged to have been in contact with Pakistan's ISI.
Radical preacher Amritpal Singh's close aide Pappalpreet Singh was on Tuesday sent to a prison in Assam's Dibrugarh, police said.
Pappalpreet Singh, who is considered to be Amritpal's mentor, was caught in Amritsar district on Monday and detained under the National Security Act.
A five-member team led by Deputy Superintendent of Police (DSP) Sanjiv Kumar on Tuesday left the city along with Papalpreet Singh for Dibrugarh Jail in Assam.
They took a flight from the Shri Guru Ramdas International Airport here.
Senior Superintendent of Police Amritsar (Rural) Satinder Singh said the team left for Dibrugarh early in the morning.
Inspector General (Headquarters) of Punjab Police Sukhchain Singh Gill told reporters in Chandigarh on Monday that Papalpreet was detained under the stringent National Security Act (NSA) and that six other cases were also registered against him.
Pappalpreet is also alleged to have been in contact with Pakistan's ISI.
Police had been conducting searches at many places, including Hoshiarpur, to nab the duo who had been hoodwinking the security men since March 18 when police had launched a crackdown against the Khalistan sympathiser Amritpal Singh and his aides.
It is believed that both Pappalpreet and Amritpal could have separated in Hoshiarpur following the police chase of their vehicle.
Khalistan sympathiser Amritpal Singh, who is yet to be caught, escaped the police net in Jalandhar district on March 18, switching vehicles and changing appearances.
He and his associates have been booked in several criminal cases related to spreading disharmony among classes, attempt to murder, attack on police personnel and creating obstructions in the lawful discharge of duty by public servants.
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)