A special court in Mumbai on Monday remanded four people, arrested in the alleged Rs 12,636-crore Punjab National Bank fraud case, in the CBI custody till March 17. The Central Bureau of Investigation (CBI) arrested them yesterday in connection with the alleged fraud perpetrated by billionaire jeweller Nirav Modi and his uncle Mehul Choksi. They were produced before special CBI judge S R Tamboli. Manish K Bosamiya, then AGM (operations) of Firestar International Ltd. owned by Nirav Modi, and then Finance Manager Miten Anil Pandya were arrested for their alleged role in the preparation of applications for fraudulent Letters of Undertakings (LoUs) submitted to Punjab National Bank.