In January 1944, the Soviet Union sent another commission, the Extraordinary State Commission for ascertaining and investigating crimes perpetrated by the German-Fascist invaders to the site; the commission's name implied a predestined conclusion. It was headed by Nikolai Burdenko, the president of the USSR Academy of Medical Sciences (hence the commission is often known as the "Burdenko Commission"), who was appointed by Moscow to investigate the incident. Its members included prominent Soviet figures such as the writer Aleksey Nikolayevich Tolstoy, but no foreign personnel were allowed to join the commission. The Burdenko Commission exhumed the bodies, rejected the 1943 German findings the Poles were shot by the Soviet army, assigned the guilt to the Nazis, and concluded all the shootings were done by German occupation forces in late 1941. It is uncertain how many members of the commission were misled by the falsified reports and evidence, and how many actually suspected the truth. Cienciala and Materski note the commission had no choice but to issue findings in line with the Merkulov-Kruglov report, and Burdenko was likely aware of the cover-up. He reportedly admitted something like that to friends and family shortly before his death in 1946. The Burdenko Commission's conclusions would be consistently cited by Soviet sources until the official admission of guilt by the Soviet government on 13 April 1990.