Rajiv Singh, Joint Director in CBI supervising the probe into Rs 13,578 Cr PNB scam, has been prematurely repatriated with "immediate effect" to his parent cadre Tripura. Three other officers including Joint Director Nina Singh, who was heading special crimes zone in CBI, has also been prematurely repatriated to her parent cadre Rajasthan. The move comes a week after CBI filed two chargesheets against Nirav Modi, Mehul Choski and top PNB officials including former MD-CEO Usha Ananthasubramanian. Officials said that the repatriation of Rajiv Singh was done by the government after Tripura C M Biplab Kumar Dev wrote to the Centre to send back the IPS officers serving on deputation in New Delhi. "Rajiv Singh has already led filing of chargesheets in PNB scam. The rest of the investigations can be easily pursued by another officer now," said a CBI official. Under his supervision in the last four months, CBI's Bank Security and Fraud Cell (BS&FC) registered over 40 cases related to major bank frauds against Rotomac, Simbhaoli Sugars, and other big names while a preliminary enquiry was initiated against ICICI Bank CEO Chanda Kochhar's husband Deepak Kochhar. Two other CBI officers of Tripura cadre, R Gopal Krishna Rao (SP) and DIG Anish Prasad have also been repatriated back to the state.