NEW YORK — Federal authorities are pressing a probe of 10 associates of Bernard Madoff despite a sentence that means the mastermind of one of the biggest financial frauds in history will spend the rest of his days behind bars, The Associated Press has learned.

A person, who spoke on condition of anonymity because the investigation is ongoing, wouldn't detail potential charges or say whether the 10 would include Madoff's family or former employees. So far, only Madoff and an accountant accused of failing to make basic auditing checks have been criminally charged in the multibillion-dollar hoax.

In court Monday, the 71-year-old Madoff admitted it was impossible for him to excuse his deeds that U.S. District Judge Denny Chin noted had cost investors $13.2 billion by conservative estimates and $50 billion by the estimate Madoff gave his sons in December.

"I don't ask any forgiveness," Madoff told Chin. "Although I may not have intended harm, I did a great deal of harm."

The judge then took his turn.

"This is not just a matter of money," Chin said. "The breach of trust was massive. Investors — individuals, charities, pension funds, institutional clients — were repeatedly lied to, as they were told their monies would be invested in stocks when they were not."

Madoff received the maximum sentence of 150 years in prison for the Ponzi scheme run at least since the early 1990s that demolished the life savings of thousands of people and wrecked charities.