Investigation is on into the Kokrajhar attack to ascertain if any other force besides NDFB(S) was behind it, Chief Minister Sarbananda Sonowal said.
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.
Security forces have launched massive operation to nab the remaining attackers who fled after the incident, the chief minister said, adding 14 civilians were killed and 19 were injured in the attack.
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.
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.
"This is a very sensitive issue and we all have to fight together against terrorism. This is a crisis. If we can stand up with determination, then we can win over this," the Chief Minister said.
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.
