Rattenhuber was promoted in rank to SS-Gruppenführer on 24 February 1945.[10] On 28 April, when it was discovered that Heinrich Himmler was trying to negotiate a backdoor surrender to the Western Allies via Count Folke Bernadotte, Rattenhuber became part of a military tribunal ordered by Hitler to court-martial Himmler's SS liaison officer Hermann Fegelein. Fegelein, by that time was Eva Braun's brother-in-law. Wilhelm Mohnke presided over the tribunal which, in addition to Rattenhuber and Mohnke, included Generals Hans Krebs and Wilhelm Burgdorf.