Katyn massacre

In April and May 1940, the Soviet secret police, the NKVD, shot nearly 22,000 Polish prisoners on orders approved by Joseph Stalin and the Soviet Politburo. The victims were army and police officers, border guards and members of the educated class captured after the Soviet invasion of Poland. The crime takes its name from the Katyn forest near Smolensk, where the first graves were found in 1943. For almost half a century the Soviet Union blamed Nazi Germany, admitting responsibility only in 1990.

Under the Molotov–Ribbentrop Pact, the Red Army invaded eastern Poland on 17 September 1939, sixteen days after the German attack. Somewhere between 250,000 and 455,000 Polish soldiers and police fell into Soviet hands. Most were soon released or handed over, but the NKVD kept many officers and officials in special camps at Kozelsk, Starobelsk and Ostashkov. Because Polish university graduates served as reserve officers, the prisoners included doctors, lawyers, engineers, teachers and writers. Over the winter they were questioned at length, a process that in effect sorted those considered irreconcilable enemies of Soviet rule.

On 5 March 1940, acting on a proposal from the NKVD chief Lavrentiy Beria, Stalin and five other Politburo members signed an order to shoot 25,700 Polish "nationalists and counterrevolutionaries". Soviet documents released in 1990 record that 21,857 people were killed from early April: prisoners from Kozelsk were shot at Katyn, those from Starobelsk in Kharkiv and those from Ostashkov in Kalinin, now Tver, with thousands more taken from prisons in occupied western Ukraine and Belarus. Victims were typically shot in the back of the head. About half of Poland's officer corps died. The victims reflected the country's mixed population and included Ukrainians, Belarusians and an estimated 700 to 900 Polish Jews.

After Germany attacked the Soviet Union in 1941 in Operation Barbarossa, the Polish government-in-exile asked repeatedly about its missing officers; Stalin claimed they had been freed. On 13 April 1943 German radio announced the discovery of mass graves at Katyn and blamed the Soviets, and Joseph Goebbels used the find for propaganda. When the Polish government asked the International Red Cross to investigate, Stalin broke off relations with it.

Moscow insisted that German troops had killed the prisoners in 1941. After retaking the area, the NKVD destroyed evidence, pressured witnesses and planted false documents, and in January 1944 the Burdenko Commission formally blamed the Germans. The Soviet prosecutors raised Katyn at the Nuremberg trials, but the charge was not upheld. Britain and the United States, according to later releases of their records, privately believed Soviet guilt was all but certain but suppressed reports that said so to protect the wartime alliance. In communist Poland the subject was censored: a 1981 Solidarity memorial reading "Katyn, 1940" was seized by police.

Archival research and Polish pressure grew in the late 1980s. On 13 April 1990, the anniversary of the German announcement, the government of Mikhail Gorbachev formally acknowledged that the NKVD had carried out the killings and expressed "profound regret". Boris Yeltsin later passed the key documents to Poland's president, Lech Wałęsa, including the 1940 execution order bearing Stalin's signature and a 1959 KGB note recording the 21,857 dead and proposing that their files be destroyed.

A Russian investigation confirmed Soviet responsibility but was closed in 2004 without classing the killings as genocide, and much of its file stayed secret. Poland's parliament has said the massacre bears the hallmarks of genocide. In November 2010 the Russian Duma declared that the crime was carried out on Stalin's direct orders, though some Russian politicians still dispute Soviet guilt. On 10 April 2010 the Polish president, Lech Kaczyński, and 95 others died in a plane crash near Smolensk on their way to an anniversary ceremony.

Our 1938 map shows the borders of Poland and the Soviet Union before the invasion; the 1945 map shows the region at the end of the war.