There is growing evidence that fraud was at the heart of the current financial crisis. But so far, no high-level bank executives have been hauled off to jail. One of the reasons may be that key bank regulators, who are counted on to root out fraud from the companies they regulate, have largely left it to the banks to report suspicious activity themselves. In this story one veteran bank regulator and a fed-up Senator try to answer the question many have pondered since the beginning of the crisis: why haven't more bank bosses been held responsible for this mess?