NK "fake employee" finds a non technical American to run their laptop farm by lying to them that running these laptops is helping make their access to some service faster.
I'm sure many, many countries have botnets. I have a bunch of those countries which I consider irresponsible and wreckless in my radar, not only north korea.
They've already arrested some people involved in this, they have devices as evidence. It's pretty well documented at this point.