“...Germany invaded Poland...”
Yeah? And 16 days later, the Rooskies took the other half of Poland.
The massacre was prompted by NKVD chief Lavrentiy Beria's proposal to execute all captive members of the Polish Officer Corps, dated 5 March 1940, approved by the Soviet Politburo, including its leader, Joseph Stalin. The number of victims is estimated at about 22,000.[1] The victims were murdered in the Katyn Forest in Russia, the Kalinin and Kharkiv prisons, and elsewhere. Of the total killed, about 8,000 were officers taken prisoner during the 1939 Soviet invasion of Poland, another 6,000 were police officers, and the rest were arrested Polish intelligentsia the Soviets deemed to be "intelligence agents, gendarmes, landowners, saboteurs, factory owners, lawyers, officials and priests".[1]