Arno Blumenthal grew up in Berlin with his brothers Rolf and James. They were categorized as Jewish by the National Socialists. After the deportations began in the fall of 1941, Arno Blumenthal managed to falsify the family’s proof of descent in East Prussia, making their father Bruno an “Aryan” and his sons “1st-grade Mischlinge.”
In 1944 Arno Blumenthal was denounced and arrested by the Gestapo, but released again because he was about to be called up into the Organisation Todt (OT). From November 1944 he had to perform heavy forced labor in an OT camp. He managed to escape from a transport to Berlin at the beginning of 1945. At the end of January 1945, he was captured by the Gestapo and put into the Gestapo prison on Große Hamburger Straße, where his false papers were discovered.
When another prisoner escaped from the camp in early April 1945, the Gestapo released Blumenthal on condition he went looking for the escaped man. Blumenthal pretended to go along with the plan. He hid for the remaining three weeks until the Red Army arrived in Berlin.