On April 27, 1945, Colonel Karl Biedermann was executed by the Gestapo and SS officers of the German Armed Forces in the suburbs of Vienna.

      On April 27, 1945, Colonel Karl Biedermann was executed by the Gestapo and SS officers of the German Armed Forces in the outskirts of Vienna. A sign reading “I made a pact with the Bolsheviks” was hung on the body. In the foreground lies the body of Lieutenant Colonel Karl Biederman of the 17th Military District of Vienna. He had joined a group of officers under the command of Lieutenant Colonel Karl Sokol, who had attempted to prevent the Battle of Vienna and the destruction of the city. The conspirators established contact with the Soviet military headquarters and planned to open a corridor to allow Russian forces to quickly occupy the city. This plot was uncovered by the SS, and Karl Biedermann and the other officers were arrested and sentenced to death by hanging by a military court.

   On April 13, 1945, Soviet troops on the Ukrainian Front completed the conquest of Vienna, the Austrian city where Hitler had spent the six years prior to World War II. By April 3, 1945, when Soviet troops approached the outskirts of Vienna, the city had already withstood over 50 Allied air raids. The Allied attacks destroyed more than one-fifth of the city's residential buildings, estimated at 80,000 apartments. Dictator Hitler issued an order from his underground bunker in Berlin to his commanders to defend Vienna at all costs. When the Soviet Army launched its attack on the southern outskirts of Vienna, the German forces defending the city consisted only of the exhausted 2nd SS Panzer Corps, anti-aircraft units, members of the Hitler Youth, and convalescing soldiers. The German forces retreated quickly to the city center without delaying the well-equipped Soviet forces. Intense fighting continued for about a week, resulting in the destruction of many of Vienna's historic buildings and severe damage to all bridges except those spanning the Danube River.

      German commanders struggled to maintain control over their scattered units, and officers relied on holding isolated positions. The Ukrainian Front cut through Vienna and advanced toward Linz and Graz. The remaining German forces retreated northward. By April 13, the Battle of Vienna had ended. Following the occupation of Vienna, large numbers of Soviet soldiers brutally treated residents and engaged in repeated looting. A state of general lawlessness persisted until Allied forces from other countries arrived to begin the joint occupation of Vienna, at which point the situation began to improve. In the Vienna offensive, approximately 30,000 German soldiers were killed, while 129,279 Soviet soldiers were killed.