All bad loan cases above Rs. 50 crore at public sector banks will be examined for fraud. This was said in a tweet by Financial Services Secretary Rajeev Kumar. "PSB (public sector bank) MDs directed to detect bank frauds & consequential wilful default in time and refer cases to CBI. To examine all NPA accounts > Rs. 50 crore for possible fraud," he said in a tweet. The direction to state-run banks come after unearthing of a massive fraud at Punjab National Bank, India's second biggest state-run lender.