In Poland comunists were in prison (before WWII)
I'm writing about Polish-speaking people within the cSoviet Union. Before 1936 they were highly represented in NKVD and their persentage in Soviet structures corresponded to the percentage of Polish-speaking population or was higher.
We don't discuss Nations now by the reason that Russia as state didn't exist in Communist period. There was a republic within Soviet Union called as RSFSR but it didn't have any army and secret police and even its Communist party (there were no such structures existing in other Soviet republics such as Ukraine or Belarus).
So we should give the analysis of ethnic groups only. Russians and Polish-speaking ethnies were as taken by their percentagies were at least equally represented in Communism within the Soviet Union. Dzerzynski or Kosior (Ukranian communist leader during great Ukranian hunger of 1933) were only the top of these activists.
One of the wrong thing Polish historians commit is the lack of interest toward Polish-speaking people life within the Soviet Union despite the fact there were mollions of such people. Not all people had enough possibility to use Optation and return Poland in 1921-1922. Only some people from west regions.
The majority of them were out of Communist activities or NKVD service (as the majority of Russians). Their difference with Russians consisted in the fact that they were by some 90% middle classers. There were also lumpens that integrated Communism and some bolchevists romantics (if romanticism can be even mentioned while we are discussing communism).
The rest was opressed by Soviet power. There were many times more victims among them than at Katyn.
I was unable to find Polish-speaking relatives of my mother despite the fact they are mentioned in Internet. The point is that all relatives mentioned are in list of those murdered in 1937-1938.
But the same situation was with Russian middle classers. I didn't feel any difference between my father's Russian ancestors and my mother's Polish speaking relatives.
The same life in fear, the same attempt to keep past in secret from children by the reason that children can tell smth. at school. The same losses of houses and lands.
The only difference was that Polish-speaking ancestors had relatives abroad and that could become known to NKVD.