Interesting stories about the 1935 Mercedes 500K, reminding me of the historian's maxim: "The Facts Never Change, But History Does Every Day." I agree with other writers that a) the car could have been stolen b) it could have been taken under the guise of spoils of war or war reparations c) someone could have given it to a soldier in return for something of
value like money, food, cigarettes, clothes, or fuel. My Dad was in the occupation of Germany in 1945 and 1946, and told me you could buy anything with cartons of cigarettes.
Speaking of reparations, has anybody heard of valuables returned to original owners after Russians removed them at the end of the war from areas in their control? It's possible, but I have never read about it. I did read a fascinating story about Russians loading up a train with valuable cars as war reparations, and an enterprising fellow purloining them one night in 1945 before they could make it to Russia: a Mercedes W158, an Alfa Romeo P3, a Maserati, and a Duesenberg.
I had never seen a W158, so had to look it up. "I'll go to town in my W158 and pick up some groceries!", said no one ever.