Hafez Mollah alias Hasan who was detained by the CID from his house at Khar Duttapa in Purbostholi, about 70 km from here yesterday, was formally arrested today, DIG (Operations), CID Dilip Adak told PTI.
Two women were arrested yesterday in connection with the blast in which involvement of terror outfits like LeT and HuJI is being suspected.
The women, Rajira Bibi alias Rumi hailing from Karimpur in Nadia and Amina Bibi hailing from Lalbagh in Murshidabad - were remanded to police custody for nine days by a local court.
Two suspected militants Shakil Ahmed and Sovan Mandal were killed and another Hasan Saheb was injured in the explosion.
Rajira Bibi is the widow of Shakil Ahmed while Amina Bibi is the wife of injured Hasan Saheb who is under treatment at Burdwan Medical College and Hospital, Burdwan Superintendent of Police S M H Mirza said.
The two women had been detained on the day of the blast. The police is on the lookout for one Abul Kalam, a resident of Mangalkote area of the district, he said.
The investigators are on his trail after they found seven calls made to him from a mobile phone immediately after the blast.