Alexander Perepilichnyy, a 44-year-old Russian man who lived in Surrey, England, was jogging near his house on November 10 when he mysteriously dropped dead, the Independent reports. After a first postmortem found no cause of death, a second was ordered.
While this would be a minor news story in most circumstances, there's one key detail that makes this a big deal: Perepilichnyy was a key witness for Swiss authorities against what is called the "Klyuev Group", a mysterious group of Russian officials believed to have been enormous tax fraud. He had fled to the UK three years ago in fear for his life.
More suspicious still, Perepilichnyy is the fourth witness involved in the case to die in mysterious circumstances.
By far the most well-known of these deaths was the that of Sergei Magnitsky, a lawyer for Hermitage Capital who acted as a whistleblower on the $200 million-plus tax fraud, before dying in police custody in 2009 after himself being accused of tax fraud. Various reports have suggested Magnitsky was beaten in prison, and was repeatedly denied medical treatment.
Magnitsky's death has become a major international incident, with Hermitage boss William Browder calling for a wider investigation, and a bill currently waiting to go to Congress that would place those suspected of involvement in the tax fraud on a black list.
A source close to the investigation told the Telegraph:
"A healthy 44-year old man who is a major cooperating witness against a transnational crime group drops dead.
"The fact that he was turning against an organized crime group makes his death suspicious by definition. This has to be treated with the utmost seriousness."
Perepilichnyy has passed a number of documents about the case onto the Swiss authorities in 2011. He reportedly lived on a "luxury private estate shared with seven multi-million pound properties".