Bangladesh Bank (BB) has issued show cause notices to the managing directors (MDs) of banks for their alleged involvement in dollar manipulation. Besides, investigation is going on against 12 other banks on the same allegation. After the removal of the treasury head of 6 banks, the central bank issued the show- cause notices against the MDs. The BB took a week for examining the authenticity of the collected documents and then  issued the show -cause notices on Wednesday. According to a BB source, a dozen more banks have been brought under the investigation. For this, foreign exchange transaction information has been sought from all these banks. Also read: Bangladesh Bank gets new governor Md Sirajul Islam, executive director and spokesperson of BB told UNB that action is being taken against the MDs of six banks due to their involvement in the dollar manipulation. “Some  other banks have been brought under investigation. Action will be taken against those banks if found guilty in the central bank investigation,” he said.