The house in West Bengal's Burdwan district where a blast occurred on October 2, 2014.

Sahanur Alam, a key accused in the Burdwan blast case, was arrested by the National Investigation Agency late on Friday night.Alam, who is alleged to be the financial brain of the terror group Jamaat-ul-Mujahideen Bangladesh (JMB), was arrested in the Nalbari district of Assam in a joint operation by Assam Police and the National Investigation Agency or NIA.The NIA had been tailing Alam since his name surfaced in the call records and interrogation of Sajid, another accused in the October 2 blast at Khagragarh in Bengal's Burdwan district.Although the investigating agency had last month arrested his wife, Alam had been on the run since the blast. NIA had also declared a reward of Rs 5 lakh for anyone providing any information about him.Alam, alias Doctor, hails from Chatala village in Assam's Barpeta district and is alleged to have arranged the money for the Indian modules of JMB.

Two people were killed in the blast which was initially assumed to be a gas cylinder blast or explosion of crude bombs. However, investigations revealed that the two people who were killed were using fairly sophisticated improvised explosive devices or IEDs.Interrogation of two women arrested from the blast site revealed that a network of terror was spread across several districts in Bengal.