Portion of stolen NEM cryptocurrency traded on 'dark web'

A portion of some 58 billion yen worth of the cryptocurrency NEM stolen in January has been traded on so-called "dark" websites, where people can remain anonymous, and part of it has been sent to an overseas cryptocurrency exchange, sources familiar with the case said.

The culprits may have been laundering the stolen NEM by exchanging it for other cryptocurrencies or legal currencies, the sources said.

The Metropolitan Police Department (MPD), which has been investigating the theft from cryptocurrency exchange Coincheck, is aware of the suspicious transactions. Investigators suspect that they constitute a violation of the Act on the Prohibition of Unauthorized Computer Access.

Transactions of NEM on the dark web began on Feb. 8, according to information security experts. By Feb. 9, about 500 million yen worth of NEM had been traded on dark websites, and as of 5 p.m. on Feb. 13, the currency had been traded on such websites on about 1,590 occasions -- a sign that the culprits stepped up their transactions over the past several days. NEM worth about 2.1 billion yen at the time of the theft -- now valued at approximately 1.15 billion yen -- may have been exchanged for bitcoins and other cryptocurrencies.

Those who traded with the culprits reportedly opened new accounts whenever they had fresh transactions, in an apparent bid to avoid being tracked by law enforcers and the NEM Foundation, which is monitoring the flow of stolen NEM. Transaction records show that some of the stolen NEM has been remitted from these accounts to Yobit, a virtual currency exchange believed to be run by a Russian company.

Those who have transactions with Yobit, which deals with a wide variety of cryptocurrencies, can remain highly anonymous as it does not require an ID when opening up an account. There are fears that it will be more difficult to get back stolen NEM currency once it is exchanged for other digital or legal currencies.

Cyber security consultant Takayuki Sugiura said those who sold stolen NEM to Yobit chose the exchange because they can remain anonymous.

The MPD has confirmed that multiple individuals traded with the culprits and already questioned one of them, a Japanese man, over his transactions. He was quoted by an investigative source as telling the MDP that he exchanged NEM for other currencies "out of curiosity."

The dark web cannot be accessed without using Tor or other software enabling anonymous communication. It is regarded as a hotbed for crimes since illegal drugs, firearms and computer viruses, among other things, are traded there.