After Germany invaded Poland on September 1, 1939, Siegfried fled with a friend. They attempted to get papers allowing them to go to France, but were turned over to the Germans. Siegfried was jailed, taken to Berlin, and then transported to the Sachsenhausen camp near Berlin in October 1939. He was among the first Polish Jews imprisoned in Sachsenhausen. Inmates were mistreated and made to carry out forced labor. After two years, Siegfried was deported to the Gross-Rosen concentration camp, where he was forced to work in the stone quarry. In October 1942, Siegfried was deported from Gross-Rosen to the Auschwitz camp in occupied Poland. While there, Siegfried tried to use his experience as a pharmacist to save ill prisoners. As Soviet forces approached the Auschwitz camp in January 1945, Siegfried was forced on a death march from the camp. Those prisoners who could not continue or keep up were killed. Siegfried survived..
And when we came there they didn't even let us into the camp. In front of the camp they right away made us work, digging the, the, the, I mean, working at the, the, at the ground and it was extremely hard, it was all granite. And not only working again, there was, uh, not the commandant, the leader of the SS was a very infamous man, rude man, young, and even small man, not strong at all, but he had a dog. He never was without the dog, and he, the dog attacked people. And we were just flabbergasted, we didn't know what's happened. After two years in another camp, you already get used to it, you know how to adjust yourself, and here you come brand new, and you start all over again, but much worse.