Question: Which high-ranking German Nazi official was assassinated in Prague in the book Mendelssohn Is on the Roof?
Context: Karl Hermann Frank (24 January 1898 – 22 May 1946) was a prominent Sudeten German Nazi official in Czechoslovakia prior to and during World War II and an SS-"Obergruppenführer".  He was tried, convicted and executed after World War II for his role in organizing the massacres of the people of the Czech villages of Lidice and Ležáky. Gottlob Christian Berger (16 July 1896 – 5 January 1975) was a senior German Nazi official who held the rank of "SS-Obergruppenführer und General der Waffen-SS" (lieutenant general), and was the chief of the SS Main Office responsible for "Schutzstaffel" (SS) recruiting during World War II.  Serving in the German Army during World War I, he was wounded four times and awarded the Iron Cross First Class.  Immediately after the war, he was a leader of the "Einwohnerwehr" militia in his native North Württemberg.  He joined the Nazi Party in 1922, but lost interest in right-wing politics during the 1920s, training and working as a physical education teacher. Herbert Otto Gille (8 March 1897 – 26 December 1966) was a high-ranking German SS commander of the Nazi era.  He commanded the SS Division Wiking during World War II.  Gille was a recipient of the Knight's Cross of the Iron Cross with Oak Leaves, Swords and Diamonds, making him the most highly decorated Waffen-SS member of the war.  After the war, Gille became active in HIAG, a lobby group and a revisionist veteran's organisation founded by former high-ranking Waffen-SS personnel in West Germany in 1951. Gregor Strasser (also German: "Straßer" , see ß; 31 May 1892 – 30 June 1934) was an early prominent German Nazi official and politician who was murdered during the Night of the Long Knives in 1934. Richard Baer (1911–1963) was a German Nazi official and commandant of the Auschwitz concentration camp. Hans Georg Fritzsche (21 April 1900 – 27 September 1953) was a senior German Nazi official, ending the war as "Ministerialdirektor" at the Propagandaministerium (Reich Ministry of Public Enlightenment and Propaganda).  He was present in the Berlin "Führerbunker" during the last days of Adolf Hitler.  After Hitler's death, he went over to the Soviet lines in Berlin to offer the surrender of the city to the Red Army on 1 May 1945.  He was taken prisoner.  Fritzsche died in 1953. Mendelssohn Is on the Roof is a book by Jiří Weil written in 1959 and first translated into English by Marie Winn in 1991.  The book took 15 years to write.  It is an exploration of the many forms of corruption in Nazi-occupied Czechoslovakia and embeds historical events, such as the assassination of Reinhard Heydrich in Prague in 1942, among fictional stories concerning the holocaust, Nazi careerism and the rise of Nazism. The Posen Conference was a meeting attended by Reichsführer Heinrich Himmler, high-ranking German Nazi Party officials and Gauleiters on October 6, 1943 in the city of Posen in Reichsgau Posen (Poznań, Poland).  Similar to his speech of two days earlier, Himmler clearly explained in the final speech of the day the nature of the Final Solution, its implications for those present, and its long-term significance for Germany. Wilhelm Kube (13 November 1887 – 22 September 1943) was a German politician and Nazi official.  He was an important figure in the German Christian movement during the early years of Nazi rule.  During the war he became a senior official in the occupying government of the Soviet Union, achieving the rank of Generalkommissar for Weissruthenien (Belarus).  He was assassinated in Minsk in 1943, triggering brutal reprisals against the citizens of Minsk.  An extreme antisemite, he is known to have said about Jews: "What plague and syphilis are to humanity, are Jews to the white race."   Reinhard Tristan Eugen Heydrich (] ) (7 March 1904 – 4 June 1942) was a high-ranking German Nazi official during World War II, and a main architect of the Holocaust.  He was an SS-"Obergruppenführer und General der Polizei" (Senior Group Leader and General of Police) as well as chief of the Reich Main Security Office (including the Gestapo, Kripo, and SD).  He was also "Stellvertretender Reichsprotektor" (Deputy/Acting Reich-Protector) of Bohemia and Moravia.  Heydrich served as president of the International Criminal Police Commission (ICPC; later known as Interpol) and chaired the January 1942 Wannsee Conference, which formalised plans for the Final Solution to the Jewish Question—the deportation and genocide of all Jews in German-occupied Europe.
Answer: Reinhard Heydrich