It may be seen as a classic case of shutting the door after the horse has bolted, but the multi-crore fraud hit Punjab National Bank appointed A.K.Pradhan as Group Chief Risk Officer, a regulatory filing by the bank said here on Tuesday.The PNB reported an additional Rs 1,300 crore unauthorised transactions, taking the estimated quantum to Rs 12,600 crore in the scam related to diamond trader Nirav Modi and owner of Gitanjali Gems, Mehul Choksi.In a late night filing on Monday with the stock exchanges, the bank said: "In continuation to our filing with stock exchanges on February 14, 2018, we have to inform that quantum of reported unauthorised transactions can increase by $204.25 million."According to PNB, Modi, Choksi and their associates worked with rogue PNB employees and used fake guarantees to obtain loans from abroad which were then illegally rolled over.