The police forces shut down Silk Road 2.0 and other sites using the Tor network, that some have dubbed the unternet of fangs.
The sites were alleged to have sold weapons and drugs, according to the BBC.
Out of those arrested, six were British and have been bailed.
The report said Bitcoins worth over £630 thousand were seized. Troels Oerling, who runs Europol’s cybercrime unit said the combined forces had closed web sites using Tor – crooks had thought themselves out of reach of the law.
Tor was originally created by the US Navy and still gets funding from the US government. It uses many different levels of encryption in daisy chains across the globe, each link being separately encrypted.