Image copyright Getty Images Image caption Sergei Magnitsky died in prison while awaiting trial

Police are analyse how 6.6 m from a Russian organised crime group has been allegedly traced to a banking firm in the UK, the BBC has learned.

US court papers have linked some of the so-called “Magnitsky money” – a 150 m tax fraud scheme in Russia – to Renaissance Capital.

The information has been handed to police by Hermitage Capital, the original victim of the Russian fraud.

City of London Police say an active investigation is under way.

Sergei Magnitsky was an auditor at a Moscow law firm when he detected what he said was a massive hoax by Russian taxation officials and police officers.

After reporting the alleged stealing of $230 m( 150 m) to the authorities, he was himself detained in 2008 on suspicion of aiding tax evasion and died in custody in November 2009.

He acted as a legal adviser for London-based Hermitage Capital Management( HCM ), where colleagues insist the case against him was fabricated to make him halt his investigations.

Despite his death Russian attorneys decided to set him on trial – a suit dismissed as a “circus” by his family and by HCM founder Bill Browder, who was himself tried in absentia.

What happened to Sergei Magnitsky ? William Browder: The human behind the Magnitsky List Image caption Mr Browder says the outcome in America should now inspire UK authorities to act