The National Investigating Agency (NIA) on Friday night arrested two persons, including a software development engineer working with a private company in Calcutta's Sector V, for alleged involvement in supplying explosives and detonators that the Bengal Special Task Force had seized from Birbhum’s Mohammedbazar last year.

A source said that Bokaro resident Mirazuddin Ali Khan and Mir Mohammed Nurruzzaman of Birbhum were arrested by the central agency from West Burdwan’s Raniganj and Bikash Bhavan in Calcutta, respectively, on Friday night.

The duo were produced before the special NIA court in Calcutta that remanded them in NIA custody for five days. An NIA source said they suspected a bigger conspiracy behind the racket and did not rule out the involvement of several influential persons.

Nuruzzaman, a software development engineer with a private company, was currently working on a project at the state education department at Bikash Bhavan. The NIA has accused him of supplying ammonium nitrate, which is an integral material for manufacturing explosives.

In June last year, the Bengal STF seized 81,000 detonators from an SUV in Birbhum’s Mohammedbazar and started a case in this connection. After interrogating the driver of the SUV, Asish Koyra, the cops recovered a large number of explosives that were illegally stored at Nalhati in Birbhum. The haul of explosives included 27,000 kg of ammonium nitrate, 1,625 kg of gelatine sticks and 2,325 electric detonators.

The NIA took over the case last September. The central agency's first arrest in the case was of "linkman" Rintu Sheikh in January.