Bought at auction, for 3.8 million, displayed at the Techno Classica in Essen, where it was seized by police, and given by the courts to claimants of being the grandkids of the original owner... a 1937 Mercedes 500 K Spezial Roadster

A court in Hamburg ruled that the historic Mercedes, which was seized by German police in April from its display at the Techno Classica car event in Essen, is the rightful property of the grandchildren of the industrialist who owned the car before it was taken by U.S. soldiers in the final days of the war

The rare car was purchased by Dutch collector Frans van Haren for nearly $3.8 million in August from the RM collector-car auction at Monterey, Calif. After shipping the spectacular roadster to Holland, he brought the car to Germany to show at Techno Classica, and was shocked when police took the opportunity to seize the car once it was back in their jurisdiction

The Mercedes disappeared while Prym was serving a prison sentence under the Allies, and his estate in Stolberg was being used as a base for U.S. troops during their march into Germany.

Photos and info from http://automotive.speedtv.com/article/vintage-german-heirs-reclaim-ownership-of-1937-mercedes-benz-500-k
 via the Vintage Racing League newsletter