A senior executive at Hermitage Capital Management has received death threats for pursuing allegedly corrupt Russian police officers in events that echo the killing last year of the hedge fund's former investigative lawyer Sergei Magnitsky.

The director, who asked to remain anonymous, has been leading Hermitage's inquiry into an alleged $230m fraud against the Russian taxpayer that implicates police. The threats, left as a phone voicemail, follow an explosive YouTube documentary about the millionaire lifestyle of one official linked to Mr Magnitsky's death who is alleged to have committed the fraud. The video has been viewed almost 200,000 times in a fortnight.

Mr Magnitsky died in prison while awaiting trial on charges of tax evasion brought by police officers whom he had testified were involved in the fraud.