The NIA team comes out after searching the madarsa in Domkol, Murshidabad, on Monday. Picture by Chayan Majumdar

Bolpur, Oct. 20: The NIA has found from a Bolpur house interconnected with three others half-a-dozen boxes with circuits that the agency suspects are used to detonate bombs.

The circuits were found on Saturday while a team of the National Investigation Agency (NIA) was searching the abandoned houses, which had holes that allowed passage from one building to another, sources said.

Wrapped in a plastic sheet, the boxes containing the circuits were found inside a well in a house belonging to Talehar Sheikh, one of the absconding suspects in the Burdwan blast case.

The four houses in Muluk village in Birbhum are said to have been built illegally on land belonging to the irrigation department.

One of the houses is owned by Dalim Sheikh, who allegedly scouted for youths to be indoctrinated by the Burdwan terror module.

The two other houses belong to Mithu Sheikh and Abdul Malek, both suspects in the case.

“We believe the interconnected houses were being used as a workshop to make IEDs (improvised explosive devices or home-made bombs) like the one in Khagragarh. We have found out that Abdul Hakim, who was injured in the blast, visited these houses several times. The circuits that were found are used to detonate IEDs,” an NIA officer said.

NIA sources said wires and switches found in one of the four houses suggested that the circuits were assembled there.

The investigators have learnt after interrogating Hakim that the module sourced explosives also from groups that pilfer gelatine sticks from the stone quarries in Birbhum’s Mohammadbazar, Nalhati, Rampurhat and Muraroi. Hakim hails from Deucha village in Mohammadbazar,

“The explosives were ferried to suspected workshops in Birbhum, Murshidabad, Burdwan and Nadia for IED manufacturing,” an investigator said.

Birbhum police sources said that during four raids this year, they had recovered about 2,000 detonators and at least 50kg of gelatine sticks from Rampurhat, Nalhati, Muraroi and Mohammadbazar.

“We had arrested half-a-dozen people involved in smuggling gelatine sticks from the stone quarries of Birbhum. We came to know from the arrested persons that the explosives are smuggled out and sold at higher rates. But we could not find out who bought the gelatine sticks and for what purpose,” a senior police officer said.

“We are investigating how much of the smuggled explosives found their way to terror modules. Initially, we suspected Maoists but now we have to examine other possibilities,” the police officer added.

Around 500 stone quarries operate in Burdwan’s Mohammadbazar, Rampurhat, Nalhati and Muraroi.

Police officers accompanying the NIA team said today: “No gelatine stick or any other explosive was found from the interconnected houses in Muluk.”

At Dalim’s house, the NIA team found about 85 small steel containers that resembled pitchers.

“Dalim was an utensils hawker. So, it was easy for him to carry the steel containers packed with explosives to different destinations,” an official said.