North Korea has reportedly used a blockchain-focused shell company in Hong Kong to launder money.

English speaking Korean news outlet Chosun reports that the United Nations’ (UN) Security Council Sanctions Committee has been prompted to investigate the situation.

According to a quarterly report from the UN committee, North Korea set up a “shipping and logistics firm run on a blockchain platform” earlier this year to evade international sanctions.

The firm, called Marine China, was run by a single individual. The head of Marine China went by two names, Julian Kim and Tony Walker, and had allegedly attempted to withdraw money from a number of Singapore-based banks.

Kim is believed to have employed another unnamed individual whose role in the firm remains unclear.

The UN committee believes that the digital currency North Korea stole last year was converted into cash and put through at least 5,000 transactions in countries all over the world. Thus making it harder to trace.

The UN estimates that North Korea‘s cyber hacking exploits have netted the Asian nation more than $2 billion.

How much money North Korea has laundered through this Hong Kong-based firm remains unclear. It still remains to be seen whether the UN’s suspicions are correct.