Ulfa (Independent) on Saturday claimed responsibility for the blast at Demow in Sivasagar district of Upper Assam that left two dead but denied its involvement in the killing of five persons at Dhola in Tinsukia district on November 1.

The Dhola case is being probed by the National Investigation Agency (NIA), which the outfit, in a statement, alleged was “immoral and corrupt’’ like “RAW, CBI, CID and MI (military intelligence)”.

The statement, issued by “major” Arunudoy Asom, assistant secretary, publicity and information wing of Ulfa (I), added, “Though we feel IB is slightly different from the rest they are not above suspicion as the recent bribery and corruption (cases) is a glaring example. NIA is not holier either. We, along with the people of Asom, have understood that investigative agencies like NIA are being used as tools by the government of India and the ruling BJP to fulfil their vindictive agenda.”

The statement said the outfit was not involved in the killing of five persons at Dhola, as the NIA has accused it of. “Our organisation made it clear in our earlier statement that we are not involved in the killing and again through this statement (we) vehemently reject this accusation and challenge the NIA to inform the people of Asom and us on what ground and proof they are accusing our organisation (of) the killing,” it said.

The outfit claimed responsibility for the Demow blast but made it clear that Arup Gupta was not their target.

On Thursday evening, Kamal Agarwalla, 45, owner of a hardware shop, and Gupta, 50, owner of a bicycle shop at Dehingmukh in Sivasagar district, were killed by an improvised explosive device planted inside Agarwalla’s shop, police sources said.

Officer-in-charge of Demow police station, Sanjib Baruah, said eight persons were detained on Friday on the basis of their call records with suspected Ulfa (I) cadres. Later, two of them and another person, whose name was revealed by those interrogated, were arrested.

Sivasagar superintendent of police Subodh Sonowal said, “During interrogation we found enough evidence against Prabhat Kahnikar and Kishore Patel (two of the eight detained) in connection with the blast. After interrogating the duo, we have arrested Manash Changmai.” The three were sent to four-day police custody on Saturday.

Sources said chief minister Sarbananda Sonowal will hold a high-level meeting on the law-and-order situation in the state in Dibrugarh on Sunday.