In the period from August 1937 to September 1938 Soviets killed 111 thousand Poles a
According to official NKVD records, they killed between 135,000 and 140,000 Poles. Others who have researched the population records put the number over 200,000. There were an estimated 1 million ethnic Poles living in the USSR in 1921. Some places remained very Polish. Vinnitsa was a Polish speaking city. According to the Riga Treaty, ethnic Poles in the Soviet Union had the right to claim Polish citizenship. Few did for whatever reason. The result was Stalin's campaign against the Poles, which was the model for Hitler's plan to remove the Jews from the Third Reich.
Considering that PiS is following Tusk's policy of discriminating against families loyal to the Second Republic, it is not surprising that the descendants of those who were not citizens before WWII are also disfavoured by the present government. In comparison to the German repatriation of ethnic Germans exiled to the East, Poland's response has been quite shameful.