Little information is published on prisons, it is one of the hidden regions of our social system, one of the dark zones of our life.
I would say, on the basis of having observe a thousand people in the experiment and having my own intuition shaped and informed by these experiments, that if a system of death camps were set up in the United States of the sort we had seen in Nazi Germany, one would find sufficient personnel for those camps in any medium-sized American town.