Bill Browder is a scammer, a vulture, who was among the first to enter Russia, with a clear desire to capitalise on the collapse of the the Soviet Union and take advantage of the monumental chaos and confusion that followed.
In the process he did make tons of money and committed all kinds of crimes, from tax evasion to illegal transactions, hoping that he would get away with it. 
The fact that he is not sitting in a Russian jail means that he did.
The fate of his accountant, Magnitsky who died in prison is an unfortunate side show that Browder is shamelessly exploiting. There is no solid proof, that he was 'murdered', only a 'conclusion' . Browder is using it trying to save/recover his (stolen) millions.
Why the Canadian government went along with this charade and lent Canada's good word to his dubious undertakings is beyond me.