The Swiss don’t think the North Koreans are responsible for $50 million worth of counterfeit “supernote” $100 bills of superior quality to real US currency. They don’t think the North Koreans have the technology.
The counterfeit bills could only be produced by a government, since only a government could afford the necessary machinery.
Who is doing the counterfeiting, and why, remains a mystery, since they evidently have not produced enough currency to pay for the costs of the necessary equipment.
Iran, Syria, and the late East Germany are other possible suspects.