"The government just believes that these assets were the proceeds of crime, are the result of criminal conduct," Jacob Frenkel, a former Securities and Exchange Commission investigator, said.

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"It does not necessarily mean that the government thinks that she is guilty," he said, referring to Madoff's wife.

Ruth Madoff has been married to Bernard Madoff for nearly 50 years, but she played no formal role at her husband's company and has not been accused of any wrongdoing.

However, she has received her share of attention during the case for mailing more than $1m worth of jewelry and watches in violation of a court order as well as withdrawing $15.5m before her husband's arrest on December 11.

Assets frozen

Bernard Madoff's business and personal assets were frozen following his arrest.

The list of assets filed in the district court includes stocks and shares, the Madoff's luxury Manhattan penthouse, homes in upstate New York and Palm Beach, Florida and their "Chateau des Pins" villa in Cap d'Antibes in the south of France.

It also lists four cars, a Steinway piano, silverware, as well as $17m in cash and $45m in bonds in Ruth Madoff's name.

Prosecutors believe that Madoff tricked thousands of clients into handing over about $177bn.

Madoff, who has denied the figure, was jailed on Thursday pending a sentencing hearing on June 16. He could face a jail sentence of up to 150 years.

A court-appointed trustee winding down his company said last month he had recovered about $946.4m for former customers.