NEW YORK -- A lawyer for victims of Bernard Madoff's Ponzi scheme said the financier told him exactly how the fraud took place during a 4 1/2-hour prison interview in North Carolina.

San Francisco lawyer Joseph Cotchett said he plans to use what he learned Tuesday to add defendants to a lawsuit to be filed in Manhattan this week on behalf of investors harmed by the fraud. He said he won't reveal before then the facts he learned in the interview.

The 71-year-old Madoff pleaded guilty in March and was sentenced to 150 years in prison. He was taken two weeks ago to the Butner Federal Correctional Complex, about 45 miles northwest of Raleigh.

Cotchett said Madoff was "very candid" and repeatedly apologized to victims.

Authorities say Madoff cost thousands of investors at least $13 billion, telling them it had grown to about $65 billion.