The U.S. has linked North Korean-backed hackers to last month’s $615 million crypto heist on the popular online game Axie Infinity.

The FBI linked the breach to a group called Lazarus, which is believed to be controlled by North Korea’s primary intelligence bureau.

The revelation came after the FBI identified the wallet used in the hack.

“Through our investigations, we were able to confirm Lazarus Group and APT38, cyber actors associated with [North Korea], are responsible for the theft,” the FBI said in a statement on Thursday.

The Treasury Department’s Office of Foreign Assets Control (OFAC) announced new sanctions against Lazarus’ identified Ethereum wallet on Thursday.

North Korea’s hacking program is reportedly used for funding the country’s nuclear and ballistic missile programs. The strategy according to a United Nations panel allows the country to bypass sanctions.

“The United States is aware that the DPRK has increasingly relied on illicit activities – including cybercrime – to generate revenue for its weapons of mass destruction and ballistic missile programs as it tries to evade robust US and UN sanctions,” a Treasury Department spokesperson said.