The Central Bureau of Investigation (CBI) has summoned an employee of an auditing firm in the multi-crore bitcoin scam in which Maharashtra politicians Supriya Sule and Nana Patole were accused by a retired Indian Police Service (IPS) officer of having a hand.

The CBI summoned Gaurav Mehta, an employee of the audit firm Sarathi Associates, hours after the Enforcement Directorate (ED) searched his property in Chhattisgarh's Raipur today.

The CBI has also filed a case against the two main accused, late Amit Bhardwaj and his brother Ajay Bhardwaj, for running an alleged Ponzi scheme using bitcoins worth up to Rs 6,600 crore in 2017.

The matter acquired a political dimension during the campaign for the Maharashtra assembly election after retired IPS officer Ravindranath Patil alleged Nationalist Congress Party (Sharadchandra Pawar) leader Supriya Sule and Congress leader chief Nana Patole were involved in the cryptocurrency fraud dating back to 2018. These funds, Mr Patil alleged, were used in the election campaign.

In the ED case, it took up investigation into the money laundering angle after the police in Maharashtra and Delhi filed first information reports (FIRs) against Variable Tech Pvt Ltd, and individuals late Amit Bhardwaj, Ajay Bhardwaj, Vivek Bhardwaj, Simpy Bhardwaj and Mahender Bhardwaj - all members of a family.

The FIRs also named a number of multi-level marketing agents who were alleged to have collected a massive amount of money in the form of bitcoins (worth Rs 6,600 crore in 2017) from the public with the "false promise" of 10 per cent per month return as bitcoins.

During the Maharashtra election campaign, the BJP latched on to the retired officer's remark and Rajya Sabha MP Sudhanshu Trivedi accused Ms Sule and Mr Patole of using illegal bitcoin transactions to influence election results.

Ms Sule has trashed the allegations and challenged the BJP to a debate on the issue. "I deny all the allegations levelled against me by Sudhanshu Trivedi. All this is conjecture and innuendo, and I am ready for a debate with any representative of the BJP at a time and date of their choice, in a public forum," she posted on X.