"In the tiny Polish village of Trawniki, the SS set up a school for mass murder and then recruited a roving army of foot soldiers, 5,000 men strong, to help annihilate the Jewish population of occupied Poland. After the war, some of these men vanished, making their way to the U.S. and blending into communities across America. Though they participated in some of the most unspeakable crimes of the Holocaust, “Trawniki Men” spent years hiding in...