It has also announced a cash reward for information on the whereabouts of Biswas.
"The arrest of Biswas is our priority and look-out notices have been circulated at all the important points. We have announced a reward of Rs one lakh for information on his whereabouts," Assam Director General of Police Mukesh Sahay told reporters here.
Biswas is absconding since the incident was reported.
Sahay said Assam Police was in touch with the other states and inter-state security agencies to trace Biswas whose "provocative" speech at an NBBUSS meeting allegedly led to the attack at Silapathar in Dhemaji district.
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Sahay also appealed to those aware of Biswas's whereabouts to contact the police and assured them that they will be rewarded Rs one lakh without their identity being disclosed.
Meanwhile, the police today arrested the founder of the NBBUSS Dhemaji district committee, Mangal Kishor Das, from Dhemaji in connection with the incident.
The police have so far arrested 27 persons in connection with the case, nine of whom were held on the night of the incident on March 6.