Bithumb, a South Korea-based cryptocurrency exchange, is being investigated by the country’s National Tax Service (NTS) for possible tax evasion.

The investigation is being led by the 4th Bureau of Investigation of the Seoul Regional Tax Service, which specializes in “special tax investigations” and agents have searched Bithumb’s headquarters in Seoul.

The investigation is examining domestic and international transactions of Bithumb Korea, Bithumb Holdings and its affiliates, and also includes observations regarding tax evasion related to the ownership of Bithumb.

This is not the first time that Bithumb has been investigated by the NTS, a similar investigation took place in 2018.

Additionally, the former chair of Bithumb, Lee Jung-Hoon, was recently acquitted of $70 million in fraud charges, and the largest shareholder and executive of Bithumb was found dead, who was under investigation for embezzlement and stock price manipulation by local authorities.