The CBI today sealed the Brady House Branch of the Punjab National Bank in Mumbai in connection with the alleged 11,400 crore rupee fraud case involving billionaire jeweller Nirav Modi and his business partner Mehul Choksi. <br/><br/>The agency posted an official notice outside the branch, which the bank's second largest national outlet. CBI had yesterday started an intensive search operation at the branch where the fraud originated. <br/><br/>The agency is also questioning Vipul Ambani, the Chief Financial Officer of Nirav Modi's Fire Star diamond company in connection with the case.