Born in 1902, Franz Oppenhoff received a law degree from Cologne University, and worked as a lawyer until World War II. Oppenhoff was an expert on Nazi law, had been legal representative for the Bishop of Aachen, Johannes Joseph van der Velden, and had defended some cases for Jewish companies. Knowing that the Gestapo was interested in him, he had taken refuge in Eupen, across the border in Belgium, in September 1944, taking his wife and three daughters with him. Following the occupation of Aachen after the Battle of Aachen, in October 1944, Allied officials wanted to appoint a non-Nazi to take over administration of the city. Assisted by the Bishop of Aachen, officials managed to make contact with a group of local business people, one of whom was willing to become the first German mayor under American rule. This was Franz Oppenhoff, who was then 42 years old. When Oppenhoff was sworn into office on 31 October 1944 no press photos were permitted and his name was not divulged, the reason being that he still had relatives in Nazi Germany who might be liable to reprisals from the Nazi regime. Also, earlier in October the SS newspaper, Das Schwarze Korps, had written that there would be no German administration under the occupation because any official who collaborated with the enemy could count on being dead within a month. In December 1944 a group of officers belonging to the US Army's Psychological Warfare Division, coordinated by historian Saul K. Padover, arrived in Aachen to assess the German population's political views and their attitude to the Nazis and the local situation. In January 1945 Padover claimed that he had discovered a "wholesale political conspiracy" in the city, centering on Oppenhoff, whose purpose was to keep left-wing forces out of stewardship. Padover reported to his superiors that the Aachen city administration "...is shrewd, strongwilled, and aggressive... Its leader is Oberbürgermeister Oppenhoff...behind Oppenhoff is the bishop of Aachen, a powerful figure with a subtlety of his own... All of these men managed to stay out of the Nazi party, most of them were directly connected with the town's leading war industries, ...These men are not democratically minded... They are planning the future in terms of an authoritarian highly bureaucratic state...Politically it is conceived as small-state Clericalism...". To make matters "worse", Oppenhoff and his associates had displayed what was seen as leniency in accepting ex-Nazis for jobs in the city administration. Padover saw to it that his story was leaked to the press so as to create sufficient uproar in the American public, and a purge of the city administration resulted, to expel former Nazis.
Operation Carnival
Oppenhoff was considered a traitor and a collaborationist by the Nazi regime, and his assassination, codenamed Unternehmen Karneval, was ordered by Heinrich Himmler, planned by SS Obergruppenführer Hans-Adolf Prützmann, and carried out by an assassination unit composed of four SS men and two members of the Hitler Youth. The unit was commanded by SS UntersturmführerHerbert Wenzel, who was a training officer at Prützmann's Werwolf training facility at Hülchrath Castle, near Erkelenz; Wenzel arranged the necessary equipment and decided on methods. Unterscharführer Josef Leitgeb, also a training officer at Hülchrath, was second-in-command. Ilse Hirsch, a 23-year-old Nazi youth leader, a Hauptgruppenführerin in the BDM was supposed to provide supplies but turned out to play an important part in the operation. Wenzel also picked a Werwolf trainee from Hülchrath to accompany them, 16-year-old Erich Morgenschweiss. Two former members of the Border Patrol completed the team, to act as guides in the area around Aachen. The unit parachuted from a captured B-17 bomber into a Belgian forest on 20 March 1945. They killed a Dutch border guard at the frontier, then moved on to set up camp near the target. Hirsch became separated from the rest and made her own way to Aachen, where she contacted a friend in the BDM and discovered Oppenhoff's whereabouts. The rest of the unit arrived in Aachen on March 25. Wenzel, Leitgeb and one other confronted Oppenhoff on his own doorstep after he had been fetched from a party at his neighbours' house. They pretended to be German pilots who were looking for the German lines. Oppenhoff tried to persuade them to surrender. Wenzel hesitated, and Leitgeb shouted "Heil Hitler" and shot Oppenhoff in the head. Just before a US patrol arrived to check the telephone line which Wenzel had previously cut, the three assassins scattered. While making their escape from the city, Hirsch triggered a landmine, which injured her and killed Leitgeb. Following the war, the surviving members of the assassination squad, with the exception of Wenzel, were tracked down and arrested. At their trial in Aachen in October 1949, all were found guilty and sentenced to between one and four years in prison, and Hirsch and one other member were set free.