Bankers are more frequently rejecting law enforcement requests to keep open accounts held for the targets of criminal probes despite assurances that the institutions won't be penalized for subsequent transactions, say sources. In 2007 guidance, the U.S. Treasury Department reiterated that banks should base decisions to maintain or close accounts on their internal anti-money laundering (AML) policies and procedures, but advised financial institutions to "be mindful" that continuing to process prohibited transactions at the request of investigators could help build legal cases against suspected financial criminals. But an unprecedented governmental focus on AML regulatory compliance has contributed to a growing...