In his book "Russia at War 1941 to 1945", Alexander Werth reported that while visiting Gdansk / Danzig in 1945 shortly after its liberation by the Red Army, he saw an experimental factory outside the city for making soap from human corpses.
Alexander Werth wrote about seeing an experimental factory outside Gdansk/Danzig in 1945. They were making soap from human corpses. He reported this in his book "Russia at War 1941 to 1945."