Replying during a Zero Hour motion raised by AIUDF MLA Aminul Islam, Sonowal said available information and evidences have revealed that NDFB(S) was behind the brutal killings.
"On this matter, investigation is going on. This is to bring to light involvement of any other force behind this incident," Sonowal said, adding one ultra was killed in retaliatory action by police and security forces.
"Police have recovered one AK-56 rifle, one grenade, lots of bullets of AK-series and one mobile phone from the site ... During investigation, numbers in the mobile and other sources have revealed that NDFB(S) was behind this (the attack)," Sonowal said.
Also 11 shops were gutted in the attack and the government has provided Rs 18.1 lakh from Chief Minister's Relief Fund as compensation to them.
Also Read
The government also provided Rs 5 lakh each ex-gratia to families of killed, Rs one lakh each to seriously injured and Rs 20,000 each to simply injured persons, the chief minister said.
Appreciating the Opposition and ruling alliance members for visiting the site and giving moral courage to the victims, he said no one should play politics over such an incident as it is an attack on Assam irrespective of caste, creed, religion and community.
Earlier, a noisy scene was created when Congress MLAs demanded a discussion over the issue saying they would support the government in its effort to curb terrorism.