The defence argument at the Enron trial, which came up with the answer to the so-called Enron corporate murder mystery , was one gamble. Putting former CEOs Jeff Skilling and Ken Lay in the witness stand was another, albeit absolutely necessary, risk.

In this analysis from Fortune, the performance of Lay and Skilling is seen as a mixed bag for both sides. There's no doubt this case has been full of surprises. The expectation before the trial for example was that Skilling would do badly. The view now, however, is that Lay, who completed his testimony on Tuesday, might have been the one who self-destructed and who blew the case for the defence.

Then comes the testimony from a highly credentialled accounting expert that Enron's treatment of its numbers was routine.

Of course, the final verdict is still to come. But with a lot riding on both sides, it's going to be a fascinating one to watch.