MOSCOW, November 28 (RIA Novosti) – A Russian supergrass, who helped Swiss prosecutors uncover alleged Russian money laundering schemes, has been found dead in Weybridge, Surrey, The Independent said on Wednesday.

The body of exiled wealthy Russian businessman Alexander Perepilichnyy, 44, was found in his luxury private estate two weeks ago, but the discovery was made public now.

The Independent said citing unidentified sources Perepilichnyy was a key witness against the “Klyuev Group”, which was implicated in a series of multi-million dollar tax frauds and the death of Hermitage Capital Management's lawyer Sergei Magnitsky.

Perepilichnyy, who sought sanctuary in Britain three years ago, is the “fourth person to be linked to the scandal who has died suddenly,” the paper said.

Magnitsky accused Russian tax and Interior Ministry officials of using Hermitage to carry out a $230 million tax fraud. He died in November 2009 aged 37 from acute heart failure after 11 months in a Moscow pre-trial detention facility.

Magnitsky was kept in appalling conditions and was refused crucial medical treatment in what Hermitage says was an effort to coerce him to admit his role in its alleged tax evasion.