The top deputy to the confessed swindler Bernard Madoff is trying to negotiate a plea bargain with federal prosecutors under which he would disclose intimate details of his boss's giant Ponzi scheme, Fortune magazine said on Friday.

In exchange for a reduced sentence, Frank DiPascali, who has worked with Madoff's firm for 33 years, would testify that he manipulated phony returns on behalf of some key Madoff investors, the magazine said. If true, it would mean those investors knew their returns were falsified, it said. DiPascali is willing to name names, the magazine said.

DiPascali's lawyer was not immediately available for comment. The magazine said DiPascali has no evidence that other Madoff family members participated in the fraud, citing a person familiar with the matter.

Madoff pleaded guilty on March 12 to charges he orchestrated Wall Street's largest financial swindle, a fraud of as much as $65 billion. He is in jail awaiting a June 16 sentencing, and faces possible life in prison.

(Reporting by Jonathan Stempel)