 He was informed that his services would be useful and soon he was a regular sight behind the German lines, repairing and polishing shoes and boots for the officers and soldiers.Unbeknownst to the Germans, however, he had also gone to Red Army headquarters to offer his services as a spy.Designated by the Red Army as the information source code named 'schoolboy', Filippov would remove documents from the desks of German officers, report German conversations and enemy troop movements, and describe what German military activity he could see to Russian officers, all while mending footwear for the German Army.