I once read a Yitzkor book written by a jew that had been enslaved during WW2 on a kulak nazi collaborator's farm in Nazi occupied Ukraine. One day he saw a Soviet military plane fly over the farm. I want to emphasize that this was in the 1940s Stalinist USSR, not even the 1950s Stalinist USSR referenced by this guy. Even in the allegedly backward Soviet Union, seeing this plane was only noteworthy to this jew because it meant help was coming soon. Seeing a flying machine didn't cause him to panic like a superstitious American.

Some days later he could hear artillery in the distance. He knew he would probably live long enough to be liberated, unlike his son and several other jewish slaves who's corpses were piled by the barn.

As the Soviets got closer, and liberation was imminent, the kulak farmer begged this jew to tell the Soviets he had been kind to his slaves.

The Soviets finally arrived, and he was freed from the misery, death, and destruction brought to him by a supposedly advanced (and absolutely not barbaric) western society.

I don't think he testified on behalf of his former owner. He didn't say, but I don't think it had to be said. There was probably no trial anyway. I'm guessing justice was swift.

In conclusion, this random internet guy that got me worked up should take Stalin's name out of his mouth.