MUMBAI: Satyabrata Kumar, a 2004-batch Indian Revenue Service (Customs and Indirect Taxes) officer who spent more than a decade handling some of the Enforcement Directorate’s (ED) most high-profile investigations, has taken voluntary retirement from service after a career marked by major financial crime probes, international extradition efforts and asset restitution initiatives.Ex-ED officer Satyabrata Kumar who probed Nirav Modi, Vijay Mallya cases takes VRSKumar’s request for voluntary retirement was approved by the Chief Commissioner, Central Goods and Service Tax and Central Excise, Kolkata, on May 19. The 48-year-old officer was serving as Commissioner (Appeals), Siliguri, West Bengal, and was relieved from service with effect from April 28.Widely regarded within the ED as a skilled investigator of complex financial crimes, Kumar spent 11 years in Mumbai between 2013 and 2024, first with the agency’s Mumbai unit and later as Special Director of Enforcement overseeing the Mumbai-headquartered Western Region. During this period, he built a reputation for his intelligence-driven investigations, extensive informant network and hands-on leadership style in tracing proceeds of crime under the Prevention of Money Laundering Act (PMLA). He had also earlier served as a staff officer to former ED Director Sanjay Kumar Mishra in Delhi.In September 2024, Kumar was posted as Special Director of the Kolkata-headquartered Eastern Region, which covers 10 states. The assignment was viewed as a key move to accelerate the agency’s crackdown on financial crimes in eastern and northeastern India, particularly online fraud and illegal gaming and betting operations, while also strengthening efforts to return seized assets to victims.During his tenure in Mumbai, Kumar supervised several of the ED’s biggest money-laundering investigations. These included the alleged ₹12,500-crore Punjab National Bank fraud involving fugitive diamantaires Nirav Modi and Mehul Choksi; the alleged ₹9,200-crore bank loan default case linked to Vijay Mallya’s Kingfisher Airlines; money-laundering and terror-financing investigations involving deceased drug trafficker Iqbal Mirchi; the Yes Bank-DHFL case involving Yes Bank founder Rana Kapoor; and the Mahadev Online Book betting and gaming probe, which uncovered the alleged role of German national Lark Marshall as one of the operation’s suspected controllers.Sources said Kumar’s team played a crucial role in gathering intelligence that ultimately led to the location and arrest of Nirav Modi in London in March 2019. The evidence collected by investigators was instrumental in India’s extradition efforts and subsequent court proceedings in the United Kingdom. Kumar is understood to have travelled to London multiple times to coordinate with the Crown Prosecution Service and participate in proceedings related to the extradition of Modi and Vijay Mallya.The investigation into Nirav Modi also involved tracking a Facebook account allegedly operated under the name “Edmond Dantes”, which investigators linked to an email address recovered during searches in Mumbai. The probe further revealed that Modi had allegedly sought honorary citizenship of Vanuatu in 2017, though the application was rejected by authorities there.In Kolkata, Kumar’s team examined alleged financial irregularities linked to RG Kar Medical College and Hospital following the August 2024 rape and murder of a trainee doctor, a case separately investigated by the CBI. His team also handled the ₹2,200-crore HPZ Token app case, which allegedly lured investors with promises of returns from non-existent cryptocurrency mining operations and exposed links to 76 Chinese-controlled entities and 10 Chinese directors.Kumar was also credited with giving momentum to the ED’s restitution programme. By July 2024, assets worth ₹15,200 crore had been returned in major cases including those involving PNB, Kingfisher Airlines and the National Stock Exchange. In August 2024, the ED constituted a dedicated Restitution Committee under his leadership. By April 2025, assets worth ₹30,751 crore had been restituted in 34 cases nationwide, including the Rose Valley Ponzi scam, where ₹515.31 crore was handed over for repayment to investors. Officials said Kumar emphasised automation and victim identification systems to speed up the process.Sources close to Kumar said he is currently pursuing a three-year Bachelor of Laws (LLB) degree and is focused on completing his legal studies before deciding on his next professional move. When contacted, Kumar declined to comment on his retirement. An ED source described him as “someone who is always looking for new challenges and never rests on past accomplishments.”