In his later diary entries, Herff claimed to have had knowledge of the Final Solution but not have played any role in administrative or actual involvement in exterminations or deportations. However, on 14–15 May 1943, Herff was in Warsaw during the Warsaw Ghetto Uprising and supervised its suppression under orders from Himmler. His adjutant, Karl Kaleske wrote of the deportations carried out following the uprising to Auschwitz concentration camp and other camps where "special action" was required. Jürgen Stroop's report on the Warsaw Ghetto Uprising contains a photograph of Herff and Stroop taken during the May 1943 visit and confirms Herff's visit to the Ghetto 14 May 1943.