The Central Bureau of Investigation (CBI) arrested Ministers Firhad Hakim and Subrata Mukherjee, TMC MLA Madan Mitra, and former Kolkata Mayor Sovan Chattopadhyay in the Narada bribery case on Monday. The central probe agency said that they have been taken to Presidency Correctional Home in Kolkata late on Monday night. They were taken from Nizam Palace, a building that houses the CBI office, to the prison amid tight security after medical tests.