A US-born financier who blamed Russian officials for the death of an employee says his visa has been revoked by the US. Bill Browder began a personal crusade against Russia after claiming several officials had been responsible for the death of Sergey Magnitsky, a worker at his Russia-based business. In a post on Twitter, he said that his visa had been revoked by the US at the same time that Russia put him on an Interpol wanted list in connection with financial crimes. Browder was a key figure in lobbying for a US law imposing sanctions against individuals he considers responsible for the death of Magnitsky. He recently testified before a US Congress commission investigating alleged Russian interference in the US election.