Lubyanka Лубянка
that was the nature of Stalin's regime, he killed millions of soviet people or made them rot in labor camps, if you can kill your own people all the more you can kill suspicious foreigners
thousands of Polish officers were executed near Katyn by NKVD, the scene of the massacre was found by the Nazis, but it's them who soviet authorities then blamed this atrocity on.
true, therefore i think had he been alive after Stalin's death, he'd be released