IT IS hardly controversial to say that Countrywide Financial, Fannie Mae and Freddie Mac were at the very centre of the financial crisis—Countrywide because it was a leading originator of subprime-mortgage loans, and the two government-sponsored housing-finance giants because they bought vast amounts of these mortgages. All three imploded.

That always made it likely that one or more of the troika would end up as targets for prosecutors. The case that finally kicked off in a lower Manhattan federal court on September 24th had all the elements you would have expected: accusations of greed, fraud and an obsession with extracting profits and sticking others with losses. But in one big respect, the identity of the defendants, it delivered a plot twist.

The company on trial is Bank of America, which purchased a failing Countrywide for $4 billion in 2008. Never mind that BofA took control after the events at issue in the case had occurred, and that it discontinued the underlying practices. It has nonetheless found itself the proud owner of a giant legal cesspool.

Even weirder, BofA’s co-defendant is Rebecca Mairone, a mid-tier executive who worked at Countrywide for only two-and-a-half years. The bank’s rise and fall came under the leadership of Angelo Mozilo, whose managerial style included running a “friends of Angelo” list that handed loans at favourable rates to politicians. But he and two other Countrywide executives settled legal claims back in 2010 without admitting or denying guilt. Ms Mairone’s attorney said his client was personally sued only because she “was an easy target, the new girl on the block.”

The prosecution’s case centres on a loan-processing system that automated Countrywide’s approval process for what appeared to be particularly creditworthy borrowers. The system was called the “high-speed swim lane” and was known by the acronym “HSSL”, pronounced “hustle”. A big issue in the case is whether this term referred merely to the speed and efficiency with which loans were processed or indicated a scam that enabled Countrywide to pick up origination fees while dumping credit risks on Fannie and Freddie. The government contends that Countrywide’s lending emphasised speed, volume and profit over quality, that it knew this created problems, and that it never relayed this to Fannie and Freddie.

The defence case is that there was no fraud; that Fannie and Freddie were experts in the mortgage market; and that they were never deceived in what they were purchasing. There will be upwards of 70 witnesses and four to five weeks of testimony; Ms Mairone will be among those taking the stand. The extended length of the trial underscores the fact that this case goes well beyond the actions of a single person or bank. No courtroom has yet heard a case against a big bank on the way the American mortgage market was operating before the crash. And although Fannie and Freddie are not on trial, the case may at last do what the government has not: subject the two politically connected mortgage giants to public scrutiny for their role in the crisis.