It appears that there has not yet been an aggressive effort by the U.S. government to prosecute those at helm of the largest financial firms that were responsible for crashing the global economy.
In the last several years there have been many civil suits brought against these firms (and their executives) that have shown overwhelming evidence of fraudulent acivities concerning the securitization of subprime home mortgage loans, and then selling the resulting complex financial "products", known as Collaterized Debt Obligations (CDO) to unwitting investors as "AAA" rated debt all the while knowing they were essentially worthless and simultaneously buying short positions on those same CDOs so that a profit could be made by the firm in question when the debt actually became worthless.