Police have raided homes across Europe targeting buyers of counterfeit banknotes made, according to Europol, by the second largest producer of counterfeit currencies on the darknet.
More than 26,000 counterfeit banknotes were purchased and delivered from the gang, according to the agency.
The estimated face value of the banknotes was around € 1.3 million ($ 1.4 million; £ 1.1 million).
In total, 11 people were arrested, 33 more suspects were detained for interrogation. Europol said a total of 36 homes in Germany, Austria, France, Greece, Ireland, Luxembourg and Spain were searched.
A printing plant in Lower Saxony, Germany, which reportedly specialized in forged documents, was also dismantled. To minimize the risk of suspects warning each other, the police conducted raids within a short period of time.
A Europol spokesman told the BBC that many of the counterfeit banknotes were sold through the Wall Street market.
The online store operated on the Tor network, which required special software to access, which meant that the site was not indexed by regular search engines such as Google.
The fake banknotes were exchanged for cryptocurrencies, which buyers used to hide their identity.
The sales were carried out through private messages and other encrypted chats with the aim of further hiding the activity.
In May, Germany’s Federal Criminal Police shut down the Wall Street market after about three years. Authorities said the site also sold illegal drugs and malware.