NEW YORK, Dec. 11 (UPI) -- Five years after New York trader Bernard Madoff's huge Ponzi scheme burst onto the nation's headlines, many mysteries remain, a lawyer close to the case said.
"We've looked at and analyzed everything that has been available to us, and we still do not understand some of the things he was doing," said David Sheehan, who represents bankruptcy trustee Irving Picard.
Picard was assigned the task of cleaning up the mess. His primary job has been to recover lost assets in a case that included a review of 33 million documents, the Wall Street Journal reported Wednesday, five years after Madoff turned himself into authorities.
With estimates of losses soaring to $60 billion and Madoff announcing that he acted alone, the Ponzi scam -- a scam that uses new client money to cover losses made with other investment funds -- was said to be the largest in U.S. history by far.
Losses are estimated now at $17 billion, but Madoff's claim that he acted alone has turned out to be a fantasy, the Journal reported.
Madoff's two sons, Mark and Andrew, who helped run the securities operation for Madoff's investment firm, have not been charged with a crime, but Madoff's brother Peter Madoff, who also ran the securities business, pleaded guilty to fraud in 2012 and is serving a 10-year sentence.
Mark Madoff committed suicide two years after the arrest of his father, who is serving a 150-year sentence.
In addition to Peter Madoff, seven other former staff members have pleaded guilty, including Frank DiPascali Jr., who was Madoff's chief lieutenant, and Enrica Cotellessa-Pitz, who was the firm's controller, the Journal said.
Five other staff members are currently on trial.
Madoff had also insisted at the time of his arrest that the firm's trading operation was isolated from the fraud – a legitimate business operating side by side with the corrupt one.
It turns out, that business was a front, Sheehan said.
"The market-making operation was his cover," Sheehan said.
Forensic accountant Bruce Dubinsky from Duff & Phelps LLC, hired by Picard, said that Madoff's trading desk lost tens of millions of dollars and was kept going by funds generated by the Ponzi scam.
Cotellessa-Pitz also admitted to transferring Ponzi funds to cover losses of the firm's securities business.
Cotellessa-Pitz called these transfers "adjustments" the Journal said.