Greece arrests Russian suspected of running $4 billion bitcoin laundering ring

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Founded in 2011, BTC-e is one of the oldest and most obscure virtual currency exchanges, allowing users to trade bitcoin pseudonymously against fiat currencies, such as the U.S. dollar, and other virtual currencies. Until today, the people behind it had remained unknown.

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It is known in crypto-currency markets as one with the most relaxed standards for checking the identity of its users to combat money laundering, and for not collaborating with law enforcement.

This helped make BTC-e "a favorite money-laundering location," said James Smith, chief executive of Elliptic, a company that works with law enforcement to track illicit bitcoin transactions. The exchange has been connected to recent ransomware attacks, he said.