Intelligence officials in South Korea reportedly believe that North Korean hackers may be responsible for the massive theft of cryptocurrency taken from the cryptocurrency exchange Coincheck earlier this year, according to Reuters .

While South Korea’s intelligence agency has not presented clear evidence to back the claim, those will knowledge of the situation believe that North Korea’s involvement in the Coincheck hack is a strong possibility.

Coincheck, a Tokyo-based cryptocurrency exchange, confirmed earlier this year that it suffered a security breach that resulted in as much as $533 million worth of digital tokens being stolen from the platform. The breach resulted in the theft of 500 million NEM tokens, which were stolen from digital wallets maintained by the company.

As a result of the breach, the Japanese exchange temporarily halted its operations. Coincheck later announced a reparation policy designed to pay back the more than 260,000 users who were affected by the breach.

Assuming the Coincheck hack was indeed carried out by North Korea, it would just be the latest example of the reclusive country attempting to generate revenue from cryptocurrency. South Korea has been making a point of pointing out North Korea’s ongoing interest in cryptocurrency despite the recent fall in value that has plagued the coins.

Earlier this week, South Korean officials claimed North Korea managed to steal large amounts of cryptocurrency from South Korea through efforts to hack cryptocurrency exchanges. While no details were provided regarding the alleged breach, South Korea has long suspected North Korean hackers of targeting exchanges hosted within the country.

Late last year, South Korean investigators began looking into North Korea’s involvement in hacks that have targeted the cryptocurrency exchange Youbit, based in Seoul. The attacks have reportedly been ongoing since April 2017.

North Korea has shown increasing interest in cryptocurrency over the last year, likely as a result of a number of factors including the sudden rise of value of many of the cryptocurrencies as well as stifling economic sanctions that have made it difficult for the isolated nation to generate revenue.

Kim Byung-kee, a member of South Korea’s parliamentary intelligence committee, said this week that North Korea stole cryptocurrency worth billions of South Korean Won (millions in U.S. dollars) over the course of the last year, mostly stolen through phishing campaigns.

Earlier this year, it was reported that North Korean hackers launched a number of campaigns that aimed to hijack computers and use them to mine for cryptocurrencies.

The effort, led by a hacking group within the country known as Andariel, reportedly took control of a server belonging a South Korean company in the summer of 2017 and used it to mine for Monero, a popular cryptocurrency that boasts privacy features that make it nearly impossible to trace the origins of transactions.

Security researchers also discovered malicious code that forced an infected machine to mine for cryptocurrency. The attack was linked directly to North Korea, as the code mining for the cryptocurrency contained a direct link to Kim Il Sung University—a college in North Korea’s capital city.

North Korea was also pinpointed as the likely culprit of the WannaCry ransomware attack that affected more than one million machines globally in 2017. The attack demanded a ransom of Bitcoin be paid in order to unlock files that the malicious software encrypted and made inaccessible.

North Korea Russia is reportedly providing North Korea with internet access.