During the Spring of 1943, tensions between the Soviet Union and the Western Allies were easening. However, recent news about the disappearance of Polish soldiers in the USSR did not work to smooth this alliance. In what came to be known as the Katyn Massacre, the bodies of thousands of Polish soldiers who had been shot in the head were found in eight communal graves in the Katyn Forest. Medical evidence proved that the Poles had been killed in 1940 by the Soviets. However, the truth was not revealed for almost fifty years.