In order to get a feel for what is happening to prisoners in North Korea, I'd suggest reading accounts of how the Nazis and Soviets treated people. For instance, an American doctor, Leo Alexander, documented the horror of the Nazi's human experimentation in a 1949 issue of "New England Journal of Medicine." Another person to read is Aleksandr Solzhenitsyn, a political prisoner himself, who tells the story of millions of people in his three-volume work "The Gulag Archipelago." I also suggest reading Richard Wurmbrand, founder of Voice of the Martyrs, "Tortured for Christ." He suffered under Nicolae Ceausescu, the brutal dictator of Romania.
We must not forget. We must educate people about this issue and find ways of helping bring this nightmare to an end.