When authoritarian states like Russia, China, and Iran take American soldiers captive, they usually demand a price for their release. Washington is concerned that North Korea may capitalize on King's defection and set a price for his return. King may have entered the hermetic country because he was running away from his legal problems and concerns of systemic racism, but the most important task right now is getting him home safely.
King illegally intruded into the territory of North Korea because of deep racial discrimination in the US Army. While Washington likes to judge other countries atop its pedestal, the US has many issues of its own that need to be addressed, including racial discrimination. A deep investigation into this case by the North's officials is well warranted.