While Yinyin’s and Jiadong’s involvement goes as far back as 2017, the DOJ’s announcement puts emphasis on a massive hack that occurred in 2018. Pyongyang hackers apparently stole $250 million from a virtual currency exchange that year and then had the funds laundered through hundreds of automated cryptocurrency transactions. They evaded being caught by using doctored photographs and false IDs. DOJ says North Korea used a portion of the funds to pay for infrastructure used in its hacking campaigns, though UN investigators also previously said that the country uses the funds it steals for its nuclear weapons program.

According to The Wall Street Journal, American officials have long suspected that Chinese actors are helping Pyongyang’s hacking efforts. However this is the first known example of the US government indicting Chinese nationals for aiding North Korea’s cyber operations. In addition to charging the accused, the US attorney’s office in Washington filed a civil action to seize the assets it believes are held in 113 virtual currency accounts. The US Treasury Department also imposed sanctions on Yinyin and Jiadong, as well as on the numerous cryptocurrency addresses they used to launder money for North Korea.