A U.S. grand jury on Wednesday indicted a Russian man for allegedly helping hackers and drug traffickers launder a total of $4 billion using a digital currency exchange. The indictment against Alexander Vinnik came after the Russian national was arrested in a small village in Greece on Tuesday, following a joint investigation between the U.S. Justice Department and other federal agencies. Federal investigators say Vinnik was the mastermind behind BTC-e, an online exchange used to trade Bitcoin currency since 2011. In addition to other charges, Vinnik allegedly laundered funds obtained from a computer hack of Mt. Gox, a Japan-based bitcoin exchange that declared bankruptcy in 2014 after hackers drained it of millions in bitcoins.