Ernst Kaltenbrunner
Heinrich Himmler became increasingly concerned about the security of documenting the destruction of the Jews. On April 9, 1943, he wrote a secret letter to Heydrich's successor as chief of the Gestapo and SD, Ernst Kaltenbrunner, concerning the Korherr Report. Himmler considered the report "well executed for purposes of camouflage and potentially useful for later times." The next day, Rudolf Brandt passed a message to the author of the report, Richard Korherr, stating: