Credit Suisse is Switzerland's second largest bank. It sold securities based upon mortgage loans to investors that led to $11.2 billion in losses. The lawsuit accuses the bank of misleading investors regarding the quality of the loans that were used to create the securities. Investors were led to believe that the bank had done due diligence on the loans in the portfolio.
All of the securitizers were doing what Credit Suisse is accused of doing. I don't know why Credit Suisse has been singled out by the NY Attorney General. Maybe this is the first of others that will follow.