Agartala, Oct 16: With the arrest of 17 people, including four of the prime accused, the Tripura CID has almost completed the investigation of the serial blasts in Agartala within a fortnight even as it is on the lookout for two others.
Police arrested the fourth prime accused Sachindra Debbarma (25) of the six main accused in the blasts yesterday and acting on his confession CID officers recovered a mobile phone from inside the septic tank of the Tripura Tribal Areas Autonomous District Council (TTAADC) headquarters at Khumlung, some 25 kms from the city last night.
Police said Sachindra Debbarma had triggered the blasts using the mobile phone in Maharajganja Bazar of Agartala and later dumped it into the tank.
Besides Sachindra, Bikash Debbarma, who was arrested earlier, had triggered blast in the Palace Compound using another mobile phone, which was recovered from an abandoned pond in Abhaynagar of Agartala.
Earlier, police arrested two others of the group, Budhu Debbarma, night guard of Pragati Vidyabhawan in the city, who had rented a room for the operation on September 10 in Abhaynagar, and Dinesh Debbarma, surrendered ATTF militant, who supplied explosives and SIM cards with mobile sets.
Two other masterminds of the incident, Satyaranjan Debbarma and Bapan Debbarma, who allegedly triggered blast using the same technique in Radhanagar bus stand, GB Bazar and planted another in Motor stand of Agartala which was defused later, were still absconding, police said.
According to the statements of the accused, the explosives were packed in containers and separate mobile sets with active SIM cards were attached to them, connecting the batteries, and when they made calls to the particular numbers, the mobile phones got activated and triggered the blast.
Meanwhile, Tripura police sought help from its Assam counterpart with the statements of the arrested militants, a group of Tiger Force activists, which revealed that the ATTF had undergone training in use of explosives under the guidance of their ally, ULFA, before being intensively trained by a group of BDR and DGFI officers at Muksinghat near Chittagong town in Bangladesh in August and September.
Tripura police informed about the details of the confession of the militants to Assam police and reportedly a team of special branch from Assam police would visit Agartala soon.
Since ULFA was suspected to have supplied the materials for manufacturing explosives and imparted preliminary training to a number of ATTF militants in handling bombs, the state authorities sought Assam's help, police said.