I read Browder's book, "Red Notice," several years ago. I've forgotten many of the details, but it was a compelling book, and plausible. He was running a hedge fund investing in the breakup of the Russian government owned enterprises, whose shares had been distributed and were being reacquired by large interests. Most of them were well-connected Russians, who became the oligarchs. Browder's investors were international.
According to the story, they did very well, but out of the blue, they were told to leave, and they uncovered evidence of Russian Government misdeeds. Their lawyer, Magnitsky, was pressured to give false testimony incriminating Browder, but refused to do so, even after imprisonment and maltreatment.
It because of the Magnitsky story as told by Browder that Congress passed the Magnitsky Act, and strangely, what Soviet Attorney Velitskaya really wanted to talk to Donald Trump Jr. about, although she used the excuse of dirt on Hillary as the come-on for the meeting.
I could believe almost anything--both of Putin and of those against him. But, here's one thing that strikes me as strange: Big players are often involved in heavy political investment. But if the amount of the purported gain that escaped taxes was $1.5 Billion, $400 million is an awful big cut for a political contribution. And, if the money was earned through trading of Russian stocks, how did it get turned into transportable, escorted cash? That kind of money tends to stay in the banking system, even the Russian banking system.
Interesting. Article BY Mr. Browder regarding Putin mentioning him by name during presser:
https://www.freerepublic.com/focus/f-news/3671583/posts