The CBI team, which has been camping in Bhopal for the last two days, registered three cases in connection with the massive rigging of examinations for recruitment in government jobs and admissions in educational institutions, naming among others a member of Madhya Pradesh Backward Classess and Minorities Commission member and his son.
The premier investigating agency also launched a probe into the "mysterious" deaths of five persons associated with the scam.
Congress leaders Jairam Ramesh and Randeep Surjewala released documents at a press conference in Delhi, based on information claimed to have been recovered from a pen drive seized from accused Sudhir Sharma by the Income Tax department.
Sharma, a mining baron considered close to the ruling establishment in MP, was alleged to have made "payments" also to Prabhat Jha, BJP National vice president, his two sons, Suresh Soni, RSS Joint General Secretary and BJP MP Anil Dave.
Besides Chouhan, the Congress leaders also demanded the resignation of Pradhan, Union Petroleum and Natural Gas Minister.