What was known in neutral countries about the on-going genocide of European Jews?

This essay seeks to understand when and through what channels countries such as Switzerland, Sweden, Spain, Portugal and Turkey learned that the Third Reich was implementing its policy of annihilating the Jews of Europe. The neutral and allied countries were well informed about antisemitic persecution conducted by the Nazi regime from its very beginning. From late autumn 1941, Germany's goal was to exterminate all the Jews on the continent. Yet it was a long time before this was understood by the Allies and the neutral states