Punjab National Bank has detected fraudulent transactions of Rs 11,000 crore in its mid-corporate branch in south Mumbai. The transactions allegedly involved a few firms promoted by billionaire diamond jeweller Nirav Modi. The bank has filed a second complaint against Nirav Modi with the CBI. CBI had earlier booked Nirav Modi in an alleged Rs 280 Crore cheating case after receiving complaint from the PNB on Jan 29.