The massacre was initiated in NKVD chief Lavrentiy Beria's proposal to Stalin to execute all captive members of the Polish officer corps, approved by the Soviet Politburo led by Joseph Stalin. Of the total killed, about 8,000 were officers imprisoned during the 1939 Soviet invasion of Poland, another 6,000 were police officers, and the remaining 8,000 were Polish intelligentsia the Soviets deemed to be "intelligence agents, gendarmes, landowners, saboteurs, factory owners, lawyers, officials, and priests". The Polish Army officer class was representative of the multi-ethnic Polish state; the murdered included ethnic Poles, Polish Ukrainians, Belarusians, and Polish Jews including the Chief Rabbi of the Polish Army, Baruch Steinberg.