The World War II mystery of what happened to a Finnish passenger plane after it was shot down over the Baltic Sea by Soviet bombers appears to finally be solved more than eight decades later. The plane was carrying American and French diplomatic couriers in June 1940 when it was downed just days before Moscow annexed the Baltic states. All nine people on board the plane were killed, including the two-member Finnish crew and the seven passengers — an American diplomat, two French, two Germans, a Swede and a dual Estonian-Finnish national.