The Central Bureau of Investigation (CBI) is probing the angle of rivalry over illegal sand mining rampant in West Bengal s Birbhum district as one of the prime reasons behind the Bogtui carnage.A total of nine persons, including the Trinamool .
In the over 20-page report, the central probe agency has also stated that the seven persons whose charred bodies were recovered from inside one of the burnt houses in Bogtui village, were "assaulted before being burnt alive".
Four people have been arrested by the CBI from Mumbai in connection with the violence that claimed eight lives in West Bengal's Birbhum earlier this year.