(NYTimes) - From the outside, the Premier Cru wine store in Berkeley, Calif., looked like a traditional, upscale wine seller. The 29,000-square-foot store was lined with tapestries, wood shelves and a “rare wine room” stocked with trophy Bordeaux and Burgundies.

Yet Premier Cru’s didn’t just sell wine off the shelves. According to court documents, it built a global, multimillion-dollar trading empire selling futures contracts for French wine to thousands of rich collectors and investors over the Internet. Now investigators and customers are looking into whether Premier Cru’s futures business was also used to fund the largest-ever Ponzi scheme in the wine world — with some of the biggest victims coming from China.

In January, facing mounting lawsuits from customers, Premier Cru filed for Chapter 7 bankruptcy liquidation. The company listed $70 million in debt and only $7 million in assets. Along with more than 9,000 victims, the crash of Premier Cru has left a trail of questions: What happened to the more than $60 million in customer payments? How did a 35-year-old wine store that became a favorite of the rich suddenly go bust? And how did so many smart collectors get bilked out of millions?

The F.B.I. announced last month that it had started an investigation into “claims of a Ponzi scheme” involving Premier Cru. The agency said that “due to the wide scope and high number of complaints” against the company, it had established a special email address for victims:[email protected] .

Premier Cru’s co-founder and owner, John Fox, could not be reached for comment. His bankruptcy and criminal-defense lawyers declined to comment.

Mr. Fox has invoked his Fifth Amendment right in declining to provide financial details on his bankruptcy or the case, according to lawyers. Creditors are seeking his 2016 Corvette and his 2014 Ferrari as part of the bankruptcy.