The man who audited Bernard Madoff's books entered a not guilty plea Friday in New York, while waiving his right to a grand jury.

David Friehling and his lawyers are trying to negotiate a plea bargain with federal prosecutors, the New York Daily News reported. Friehling, now free on $2.5 million bond, could receive a 105-year prison term if convicted of all charges.

U.S. District Judge Alvin Hellerstein scheduled a hearing date for Oct. 1.

Friehling, who was Madoff's accountant for 17 years, is the only other person charged so far. Madoff has begun serving a 150-year sentence, effectively a life term, after admitting his investment business, which had been posting steady returns of about 10 percent a month for years, was a Ponzi scheme.

Federal prosecutors say that for 17 years Friehling signed off on Madoff's accounts without seriously examining them.

Investigators are trying to determine if anyone else was involved in the fraud.