A West German military historian flew to Yugoslavia in an effort to authenticate a World War II telegram said to link President Kurt Waldheim of Austria with Nazi war crimes. But if such a telegram exists, it seems to have disappeared, said Manfred Messerschmidt, a member of a Vienna commission reviewing Waldheim’s service in the German army. The purported telegram came to light when Der Spiegel, a West German magazine, published what it said was the text of a wartime message from Waldheim demanding “4,424 prisoners from Kozara . . . be sent . . . to Grubisno Polje and to Zemun.” The latter were Yugoslav collection points for prisoners, where some executions took place.