Jurors in the first criminal trial to result from Bernard Madoff's epic fraud may soon start weighing whether five of his former employees were his conspirators or his dupes.

A Manhattan federal jury could start deliberating as soon as Friday in the five-month-long trial. Closing arguments are expected to wrap up, followed by lengthy legal instructions and possibly the start of deliberations.

Madoff has said he acted alone in cheating thousands of investors out of nearly $20 billion in a decades-long Ponzi scheme. But federal prosecutors say five back-office subordinates gave him vital help in weaving his financial fiction.

The defendants say they, like Madoff's investors, were fooled by a master at deceit.

Madoff pleaded guilty and is serving a 150-year prison sentence.