The brother of imprisoned financier Bernard Madoff was sentenced Thursday to 10 years in prison for crimes committed in the shadow of his notorious sibling by a judge who said she disbelieved his claims that he did not know about the epic fraud.

Peter Madoff, 67, had agreed when he pleaded guilty in June to serve the maximum sentence allowable to the charges of conspiracy and falsifying the books and records of an investment adviser.

He follows to prison his 74-year-old brother, who is serving a 150-year sentence after admitting he created a fraud so large decades ago that thousands of people lost $20 billion.

Photo: CTV

In this April 3, 2009, file photo, Peter Madoff, brother of Bernard Madoff, attends a court hearing before judge Stephen Bucaria at Mineola State Supreme Court, in Mineola, N.Y. (AP Photo/Louis Lanzano)

U.S. District Judge Laura Taylor Swain urged Peter Madoff to tell the truth even now about what he knows about the fraud that cost thousands of investors their original $20 billion investment.

The judge said Peter Madoff, wearing a well-tailored charcoal suit, was "frankly not believable" when he claimed at his plea that he only learned of the fraud when his brother revealed it to him just before he surrendered to authorities.

Peter Madoff spoke only briefly, saying: "I am deeply ashamed of my conduct and have tried to atone by pleading guilty and have agreed to forfeit all of my present and future assets."

He added: "I am profoundly sorry that my failures let many people down, including my loved ones."

Two investors, among 40 who wrote victim impact statements, spoke during the proceeding, each describing the financial ruins of their extended family.

Investor Michael T. De Vita, 62, also called for truth, saying he believed "it to be physically impossible for a single person to carry out such a gargantuan task all by himself."

De Vita said investors "have waited four years for others to accept responsibility for this massive crime. We are still waiting for that today."