India's Central Bureau of Investigation (CBI) has arrested Ayush Varshney, co-founder and chief technology officer of Darwin Labs Private Limited, in connection with the GainBitcoin cryptocurrency fraud case. Varshney was detained at Mumbai airport while attempting to leave the country, following a Look Out Circular issued against him. The CBI alleges that Darwin Labs was instrumental in developing the technological infrastructure for the GainBitcoin scheme, which involved approximately 8,000 investors and losses estimated at 6,606 crore rupees ($790 million). The GainBitcoin scheme, promoted through Variabletech Pte. Ltd., promised investors monthly returns of about 10% in Bitcoin for up to 18 months. However, the CBI claims that funds were misappropriated, and the scheme eventually relied on a multi-level marketing structure. As new deposits dwindled, payouts shifted from Bitcoin to the less valuable MCAP token. The operation was allegedly led by Amit Bhardwaj, who passed away in 2022. The investigation continues as authorities seek to unravel one of India's largest alleged cryptocurrency frauds.