Browder tweeted about the saga in Madrid.
Natalia Veselnitskaya was a driving force in the effort to repeal the 2012 Magnitsky Act.
Nikolai Gorokhov represents the family of Sergei Magnitsky, who died after exposing tax fraud by Russian officials.
It has to be more than a coincidence that the recent cyber theft of IRS tax data has been traced to Russian criminals. IRS investigators believe the identity thieves who stole the personal tax information of more than 100,000 taxpayers are part of a sophisticated criminal operation.
For the last few weeks commentators, politicians and many sectors of the western public have been perhaps surprised by Vladimir Putin's somewhat reconciliatory tone towards the U.S. and the West.
We discover, laid bare by an expert, the inner workings of the staggering extortion scheme that is the heart of Putin's system, and we understand that the act of revealing those workings is the most unforgivable crime in the country.
Browder was the largest foreign investor in Russia until 2005, when he became blacklisted from Russia as a "threat to national security." He has since emerged as one of Putin's most strident critics, and a prominent human rights activist.
Far from falling back into line and yielding to terror, tens of thousands of Russian men and women, in the manner of the French who so recently proclaimed "Je suis Charlie," came out to shout "I am Boris" into the ears of Vladimir Putin, who has never faced an adversary as vibrantly alive as this newly dead man.