In 2012, wine counterfeiter Rudy Kurniawan was arrested for producing and selling an estimated $550 million worth of fake fine wine. In 2016, wine authentication experts estimated the counterfeit luxury wine category to be worth as much as $3 billion.

But it’s not just prestigious labels drinkers should be wary of. In January, two Prosecco producers were “caught” adding extra sugar to grape must, breaking the region’s strict DOCG regulations.

Now, days later, reports are emerging from Italy that over “50 entities linked to Italian wine production” are currently under investigation for fraud, including mislabeling wines and using grapes not permitted under regional appellation regulations.

The dubious practice was allegedly uncovered by a “sting operation” earlier this week, the Daily Beast reports. A full list of the brands under investigation is yet to be released, but reportedly include prestigious wines from Pordenone, Udine, Treviso, Venice, Padova, Reggio Emilia, Modena, Ravenna, Florence, Livorno, Naples, and several cities in Puglia.

It’s not only wine producers believed to be involved; according to the Daily Beast, the inspectors responsible for certifying the wineries in question are also being investigated for complicity.

Further details are expected to emerge next week.