13. The Alsos mission moved into Germany in early 1945
By March, 1945, Alsos teams returned to Strasbourg, and opened another facility in Aachen. From there analysis of captured documents revealed extensive atomic research in several locations, some still out of reach of the Allied Armies. When Alsos missions identified an industrial facility at Oranienburg as a thorium and uranium processing site, General Groves prevailed on the 8th Air Force to bomb the facility. Plans called for the Soviets to occupy the site post-war. The still persistent rumors of the German’s possessing atomic weapons ensured ready cooperation from the Army Air Force, and Alsos used the fear to their advantage. Over 600 bombers pounded the Oranienburg site; the bombing forced several of the most senior German scientists involved in the processing of uranium to flee eastward. There they fell into the path of the Soviets, who had created an Alsos team of their own.
The Americans were soon aware of the presence of Russian atomic scientists in NKVD uniforms in Oranienburg and other targeted regions. The Soviets too captured several German scientists, including Nikolaus Riehl and Gunter Wurths, who directed the uranium processing efforts at Oranienburg. When the Soviets requested a meeting with the German scientists in Berlin shortly after capturing the city, the Germans complied. They found themselves transported to the Soviet Union shortly thereafter. As Riehl awaited transport from Berlin, Soviet operatives dismantled his temporary laboratory and sent it to the Soviet atomic weapons program site in the Soviet Union. The Soviets recovered almost 100 tons of processed uranium oxide from the Oranienburg site, an indication their own atomic weapons program had advanced further than previously suspected.