Unlike North Korea, I was born in the USSR and saw all that with my own eyes, and I personally know several dissidents who were imprisoned in the 1980s. To suggest that she had any freedom of speech, particularly to a foreign journalist, is deeply ignorant of the conditions at the time. People were scared to openly talk even with their relatives from the West. In 1974, a foreign journalist heard only what the KGB wanted them to hear.
Meanwhile, in that time, Solzhenitsyn was outed as a conspiratorial antisemite.
If you want to opt into a goofy American spy movie, be my guest, but your arbitrary choices of who is believable and who isn't are utterly unconvincing.
As to the crimes themselves, they've been meticulously documented by human rights organizations like Memorial. https://en.wikipedia.org/wiki/Memorial_(society)
Edit: well, not entirely - https://news.ycombinator.com/item?id=35469335 was bad. Please stay within the rules when commenting on HN.
If you like those horror stories check out the North Korean ones, they have oodles of stuff about people dying and reappearing, being shot out of cannons, eating human faeces, and whatever else the human imagination can come up with.