Chris Fields said Sunday that forensics accountants looking into the missing millions believe they were invested with Madoff through a third-party money manager.
He says the loss was noticed about a week ago when Gabor's husband Frederic von Anhalt was checking on the couple's finances.
Madoff is estimated to have duped investors out of as much as $50 billion in a large-scale Ponzi scheme. Potential victims include several high-profile New Yorkers and Hollywood figures.
The deadline for prosecutors to deliver a formal indictment of Madoff is Feb. 11.