Blockchain analytics provider Elliptic revealed that the four Russian sites earned a total of about $263 million in digital assets through illegal transactions. The three most commonly used cryptocurrencies are bitcoin (BTC), ethereum (ETH) and litecoin (LTC).

According to Trustwave SpiderLabs, members of the underground forum believe their countries are no longer safe havens and fear arrest. Some have suggested moving their ransomware operations to India, China, the Middle East or Israel.

The three men, who work for a private detective agency, used the dark web to sell addresses, phone numbers and other personal data to paying customers, according to law enforcement sources cited by TASS. The group allegedly used forged court orders and falsified police documents to obtain the information.

Five members of a nationwide criminal gang have been arrested in Moscow, Rostov, Astrakhan and Krasnodar regions, TASS news agency reports.