A prosecutor has started closing arguments in the New York trial of five ex-employees of Bernard Madoff by telling jurors that each of the defendants played a "crucial role" in the mammoth fraud.

Prosecutor John Zach said Tuesday that Madoff depended on his former secretary, his former head of operations, an account manager and two computer programmers to keep his fraud alive for four decades. It collapsed in December 2008 when he ran out of money and confessed to FBI agents that his business was a sham. He pleaded guilty and is serving a 150-year sentence at a federal prison.

The closing arguments come as a nearly six-month trial winds down in Manhattan. All of the defendants have pleaded not guilty and two of them testified.