U.S. authorities said the elaborate tax fraud and money laundering allegations were first uncovered by Sergei Magnitsky, Russian accountant for investment firm Hermitage Capital. After accusing Russian officials of the $230 million tax fraud, he was arrested on tax evasion charges and died in prison a year later, prosecutors said. The Kremlin's human rights council found that Magnitsky likely died from a beating delivered by guards and medical neglect. Russian authorities have said Magnitsky death was caused by heart failure, not foul play. In 2012, at the urging of Magnitsky's former employer, Hermitage Capital CEO William Browder, Washington passed a law freezing any U.S. assets of Russian investigators and prosecutors said to have been involved in the accountant's detention. In retaliation, Moscow barred Americans from adopting Russian children