May 24: A day after the Matghoria blast, intensified counter-insurgency operations have yielded results with the arrest of four Ulfa rebels and sympathisers suspected to have been involved in the blast.

Two of the four were arrested after a brief but fierce encounter with the police at Lotakata in Basistha last night. Two other suspected Ulfa sympathisers were picked up from Rongjuli in Goalpara district late last night.

The police have also identified the masterminds of Matghoria blast as Rontu Goyari and Pradip Rajbongshi. Members of the Ulfa?s 109 battalion, they are said to be operating under the outfit?s explosive expert Hira Sarania. Goyari hails from Morigaon district while Rajbongshi is from Nalbari district.

The police do not have any clue about their whereabouts, but ?efforts are on to locate them before they strike again,? a source said.

In Lotakata, a police team raided a house in the area acting on specific information. As soon as the police encircled the house, Ulfa rebels opened fire from inside, leading to the encounter.

One militant fled under cover of darkness, but two of his associates were rounded up. They have been identified as Bimal Hajowary and Mausam Saikia. According to the police, Hajowary is a resident of Panjabari locality while Saikia is the owner of the house where the militants were taking shelter.

The rebel who escaped has been identified as self-styled sergeant major Raju Baishya. ?A hunt is on to trace Baishya who is suspected to have sustained injuries during the encounter,? a police source said.

No policeman was injured in the encounter.

Explosives such as five detonator sets, those used in programmable timer device and fuse wires were seized from the Ulfa hideout. ?The two arrested were involved in the activities of the militant outfit in the city for long. The recovery of explosives from them has fuelled suspicion about their involvement in the Matghoria blast. However, the picture will be clear only after their interrogation is over,? a police official said. Top police officials are interrogating Hajowary and Saikia at the Basistha police station.

In the Rongjuli incident, the two Ulfa sympathisers picked up by city police have been identified as Ranjit Rabha (26) and Iswar Agarwala (40).

?While probing yesterday?s blast, we received information from a source about their involvement in the incident. On the basis of that tip-off, they were picked up from Goalpara and brought to the city today,? a police source said. He, however, refused to say what kind of involvement Rabha and Agarwala had in the Matghoria blast. They, too, are being interrogated.

A police source said the raid at Lotakata was carried out last night on the basis of information provided by two Ulfa militants, who had been nabbed on May 22 night.

These two militants, Abdul Hatim alias Nibaran and Bimal Rabha, had been rounded up along with two other Ulfa militants by the army from Kumarikata near Tamulpur in Nalbari district on the basis of information provided by city police.

Hatim and Rabha revealed during interrogation that Ulfa militants were taking shelter at Lotakata. ?An improvised explosive device (IED) similar to that used in Matghoria was recovered by the army from Hatim. He had told the army that one such device had been sent to the city and we suspect that it is the one used at Matghoria,? a police source said.