Plans for the brother of jailed financier Bernard Madoff to plead guilty and serve 10 years in prison raise fresh questions about the status of the investigation into the epic multibillion dollar fraud and whether other family members remain under criminal investigation.

U.S. prosecutors notified a judge and victims Wednesday that Peter Madoff will plead guilty Friday to conspiracy and falsifying records charges more than three years after his brother began serving a 150-year sentence for creating the fraudulent multibillion dollar private investment business.

Bernard Madoff claimed that he acted alone as he enticed thousands of investors over several decades to join what became the largest Ponzi scheme ever prosecuted in U.S. history.

Peter Madoff was the former chief compliance officer at the private investment arm of Bernard Madoff's business. Prosecutors say he has agreed to the criminal forfeiture of $143 billion, including all of his real estate and personal property. The $143 billion, representing the amount of money believed to have flowed through the business accounts when he was part of the multi-decade Ponzi scheme, is included in a criminal forfeiture agreement, though authorities know that his assets would only amount to tens of millions rather than billions.

Court papers signed by a federal judge in Manhattan on Wednesday show Peter Madoff, who had worked with his brother since 1965, plans to plead guilty to two criminal counts, admitting his role in a conspiracy to commit securities fraud, falsify records of an investment adviser, falsify records of a broker dealer, make false filings with the Securities and Exchange Commission, commit mail fraud and obstruct the Internal Revenue Service.

Assistant U.S. Attorney Lisa A. Baroni wrote in a letter to U.S. District Judge Laura Taylor Swain that, pursuant to a plea agreement with the government, Peter Madoff, 66, had agreed "not to seek a sentence other than 10 years' imprisonment."

Charles Spada, a lawyer for Peter Madoff, declined to comment.

Bernard Madoff, 74, is serving his prison term in Butner, N.C., after revealing in December 2008 that he cheated thousands of investors of roughly $20 billion for years, using money from new investors to pay returns to existing clients. Lawyers for a court-appointed trustee recovering money for Bernard Madoff's investors had said Peter Madoff also was the company's senior managing director.

The trustee, Irving Picard, said in court papers that Peter Madoff "failed miserably" to meet his responsibilities to monitor the company's operations and ensure its compliance with federal securities laws.

The court papers said Peter Madoff had received at least $60 million during the fraud and used fake stock trades to make large withdrawals seem justified.

Picard sought nearly $200 million from Madoff family members, claiming they used Bernard L. Madoff Investment Securities LLC as "the family piggy bank" to pay for vacation homes, cars, boats and even a stake in a beauty parlor.

Picard's pending lawsuit alleges that over the years, Peter Madoff, his daughter and his nephews "withdrew millions more than they invested" in private investment accounts they had with the firm.

Peter Madoff "ignored obvious red flags that the profits reflected in account statements could not have been earned legitimately, to the detriment of BLMIS and its other customers," the lawsuit says.

Bernard Madoff's relatives have said they did not know about his Ponzi scheme. His brother's plea raises new questions about the status of the prosecution and whether other family members are being targeted by the government.

Lawyers for Andrew Madoff, a son of Bernard Madoff, and Shana Madoff, Peter Madoff's daughter, did not immediately return messages for comment. A lawyer for Bernard Madoff's wife, Ruth, did not immediately return a message seeking comment. Mark Madoff, Bernard Madoff's other son, committed suicide in December 2010 on the second anniversary of his father's arrest.

Six former employees and associates have pleaded guilty and are cooperating. Five others, including Madoff's former operating chief, have pleaded not guilty and appear headed to trial.

Picard has accused Andrew Madoff of living a high-end lifestyle after receiving more than $60 million, including $31 million in salary and bonuses, from 2001 to 2008.

Shana Madoff, a lawyer, had worked at Madoff's investment business since 1995 as compliance counsel and in-house counsel. Picard's civil lawsuit said that "she ignored every red flag of the massive fraud taking place right in front of her."

The huge scheme, run since at least the early 1990s, demolished the life savings of thousands of people, wrecked charities and shook confidence in the U.S. financial system. When Bernard Madoff pleaded guilty, he insisted that he acted alone, describing a separate wholesale stock-trading firm run by his sons and brother as honest and legitimate.

So far, Picard's office has reached agreements to recover approximately $9.1 billion and has distributed more than $1.1 billion to Madoff's victims.

In a statement Wednesday, Picard's spokeswoman, Amanda Remus, said the trustee and his lawyers are aware of the letter to the court about the anticipated guilty plea proceeding involving Peter Madoff but had no comment.