NEW YORK — Bernard Madoff's contention that he pulled off one of the biggest financial frauds in history without any help is being met with disbelief by his investors and experts in the securities industry.
It normally takes a team of accountants, stock brokers, lawyers and more to operate the kind of multibillion-dollar investment fund that Madoff ran from the 17th floor of his Midtown Manhattan headquarters.
The firm had clients around the globe. Simply generating the detailed financial statements investors got in the mail every month would have been a monumental effort for just one person, observers said, even if those reports were pure fantasy.
"Someone had to create them. Someone had to create the appearance that there were returns," said attorney Harry Susman, who represents several Madoff investors.
"The guy was 70 years old. Could he have done it himself? The computer systems would have needed to be extensive. Supposedly, he's selling puts, buying puts, selling calls, buying stocks. Somebody had to sit there and buy stocks. Where are these people?"
Federal investigators are still in the early stages of trying to answer those same questions as they decipher Madoff's operation. Already, they have discovered multiple sets of books and what appear to be fraudulent documents in his Manhattan offices, raising the question of who prepared them. It may take time before they can say whether he had accomplices.
Investigators have started serving grand jury subpoenas requiring witnesses to testify and seeking documents, according to an official familiar with the case. The official, who spoke on condition of anonymity because the investigation is ongoing, declined to identify who was served or specify what documents were wanted.
The investigation has been unfolding in a Manhattan office that was once Madoff's sanctuary but is now the site of a nonstop hunt for incriminating documents, with boxes of confiscated records stacked in the hallway.
"Every time I go out my office door to go to the ladies' room I've been tripping over FBI agents," said Muriel "Mickie" Siebert, whose namesake brokerage firm shares the 17th floor of the office building.
The investigation is being led by the FBI and Securities and Exchange Commission — agencies already challenged with unearthing other financial scandals since the Wall Street meltdown.
One potential subject of the inquiry is the role played by Frank DiPascali, a top financial officer at Madoff's investment advisory business.
Several investors, their lawyers and a former Madoff employee who spoke to The Associated Press described DiPascali, of Bridgewater, N.J., as the man who appeared to be most responsible for the day-to-day operations of the business.
When clients had questions about the firm's investment strategy or its performance, DiPascali was the one who got on the phone. If they wanted to add or subtract money from their accounts, DiPascali made the arrangements and distributed the checks.
Authorities haven't publicly accused DiPascali of any wrongdoing. His attorney, Marc Mukasey, on Thursday declined to discuss his client's role or say whether he became aware of the fraud prior to Madoff's arrest.
"We are sitting with our client and reviewing his career at Madoff and his duties and responsibilities," said Mukasey, the son of U.S. Attorney General Michael Mukasey. "I understand that people are extremely frustrated and upset ... We would love to see people get as much of their money back as possible."
Questions also loom about Madoff's auditor, Friehling & Horowitz, a relatively unknown accountant in the city's northern suburbs who appeared to operate from a one-room office with irregular business hours and a bare-bones staff.
Those audits apparently failed to detect the fraud, which Madoff told investigators was a Ponzi scheme that lost an estimated $50 billion.
The firm's principal, David G. Friehling, has not answered his telephone in days. His attorney, Andrew Lankler, declined to comment Thursday.
Investigators were also expected to look at the potential involvement of several Madoff relatives who worked for his firm, including his brother, two sons and others who worked for his various business entities. His wife has also come under scrutiny.
To date, however, they also have not been formally accused of any wrongdoing.
The law firm representing Madoff's sons, Andrew and Marc, released a statement saying they first learned of the fraud just days ago, when their father tearfully confessed, and immediately turned him in. The two are said to have worked predominantly in another division of their father's company, not in the secretive unit that handled investor money.
By some accounts, Bernard Madoff appeared to take unusual steps to limit the number of people and outside companies that had a hand in running the business.
Much of the recruiting of new investors to his funds was done informally, by friends, or through a group of large, independently managed feeder funds, who also took most of the management fees for handling the investments. They included the Fairfield Greenwich Group, which put all $7.3 billion of its Fairfield Sentry Fund in Madoff's hands.
It was unclear whether authorities were looking to see whether any of those funds, whose investors have emerged as some of Madoff's largest victims, may have been complicit in the scheme. Each has claimed no knowledge that anything was amiss.
Usually, a fund like Madoff's would use an outside brokerage firm to complete its stock trades. In his case, those duties — if they actually occurred — were apparently handled in-house.
He appeared not to have hired outside professional services firms to help calculate his performance or to produce electronic data for investors.
"He was still doing it the way you did it in the 1960s, with a paper ticket," said Suzanne Murphy, a hedge fund consultant who had examined Madoff's business two years ago before deciding not to invest in it.
"In most hedge funds, you have many partners in deals, but he was doing everything in a self-contained way," said Jake Walthour, head of advisory services for the due diligence firm Aksia LLC, which also examined Madoff's operation and decided something was wrong.
That lack of partners made it tough to verify that Madoff's business was really achieving good returns. It may also reflect an effort to limit the number of possible accomplices.