Pre-trial hearings of former employees of the Berlin Gestapo for deportation of Berlin Jews to extermination camps: Statements by former employees of the of the RSHA "Jewish Department" (Judenreferat) and of Gestapo offices in Berlin, Cologne and Duesseldorf, especially regarding the extent of knowledge of Gestapo employees regarding the fate of the deported Jews; testimonies by Berlin Jewish survivors, 1967-1968