Peter Madoff, the beleaguered younger brother and business partner of the infamous Bernard Madoff, is set to plead guilty Friday to charges stemming from Wall Street's biggest Ponzi scheme, federal prosecutors disclosed late Wednesday.

In a letter filed in federal court in Manhattan, prosecutors said Peter Madoff, 66, will plead to a criminal information charging him with securities fraud, as well as related charges, and is expected to be sentenced to up to 10 years in prison.

Peter Madoff, of Old Westbury, had long denied through his attorneys that he had any involvement in the massive Ponzi scheme that cost investors an estimated $17 billion to $20 billion when it unraveled in December 2008.

According to the prosecution's letter, Madoff is expected to admit by his guilty plea that he made false statements to investors about the Madoff firm's investment advisory business and its compliance program, which he oversaw.

He also will plead guilty to falsifying records, making false filings with the Securities and Exchange Commission and obstructing the Internal Revenue Service.

Defense attorney John Wing of Manhattan didn't return a telephone call late Wednesday seeking comment.

In addition to a prison term, Madoff also will agree to forfeit $143.1 billion, an amount that represents the total illegal proceeds of customer monies that passed in and out of the Madoff company while he worked there.

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Bernard Madoff pleaded guilty in 2009 to running the Ponzi scheme and is serving a 155-year prison sentence in North Carolina.