Korean news site dongA reports: "Jeong and his ring reportedly sold the game money illegally produced in China using cheap labor and virus programs. They are believed to have taken a commission of three to five percent of the money traded to purchase game money."
The story comes to use from security-focused site PlayNoEvil, which adds: "Korean police busted the leaders a money laundering group for a Chinese Gold Farming ring (the relationship between the two groups is unclear) which targeted Korean online games. The group smuggled $38 Million over 18 months (!) from Korea to China... Apparently the organization had a pool of IP addresses that made the gold farming group appear to be located at a Korean internet cafe."
In addition to the men arrested in connection with the money laundering, charges have been filed against 11 Korean citizens whose bank accounts were being used by the ring. If any further clarification on the bust becomes available, this post will be updated to reflect that.