Key insight: The case against Berkshire Bank, which includes unusually detailed allegations, represents the latest test of the law in cases where bank customers commit fraud.Supporting data: The Ponzi scheme's operator allegedly solicited $90 million from roughly 1,000 investors, promising them an 8% return on their money.What's at stake: Banks can be sued over whether they responded appropriately to what their customer due diligence efforts have revealed.Less than two weeks after completing a merger, Berks ...