Matti Nissinen urged the authorities to keep an eagle eye on such new forms of international crime being spread by an anonymous and decentralized network of websites that exist off the grid and out of the sight of Google, Facebook and conventional Web browsers.
To keep payment out of sight, transactions are made with Bitcoin, a digital currency that is similarly decentralized and nameless.
Such websites are fueled by the perception that buying and selling services through virtual money is safe and anonymous.
Virtual money has been around since the mid-1990s. But the rise of Internet currency has fueled a global crime wave.