The blast took place around 5 am when a joint team of the CRPF's special jungle warfare unit, CoBRA, and the state police was carrying out an operation in the forests of Kuchai area in the district, officials said.
In Bihar, caste violence erupted like a plague in the late 1990s. There was the armed Ranvir Sena, composed mostly of Bhumihar landlords, baying for Dalit blood. And then there were retaliatory strikes of Maoist groups.
Prof Shoma Sen was arrested under the Unlawful Activities (Prevention) Act, as were activists Rona Wilson, Mahesh Raut and Sudhir Dhawale, and lawyer Surendra Gadling as part of the police probe into the violence at Bhima-Koregaon.