A lawyer for the family of a dead Russian whistle-blower was badly injured after falling from the fourth floor of his Moscow apartment building the day before he was due to appear in court to prosecute a corruption case.

According to a statement by Bill Browder, a British businessman who knows lawyer Nikolai Gorokhov and has campaigned against corruption in Russia, Gorokhov was thrown from the balcony and suffered severe head injuries.

Browder did not provide a source for his claims.

He said in a statement on his website Law and Order in Russia, Gorokhov was due to appear in an appeals court in Moscow today (22 March) to contest its refusal to investigate allegations of organised crime.

The case was brought by late white-blower Sergei Magnitsky's mother.

Russian state media reported that Gorokhov fell when a rope snapped when he and others were attempting to lift a bath into the apartment.

Gorokhov had previously represented the family of Magnitsky, a lawyer who died in prison in 2009, aged 37, after claiming that government officials had colluded with organised crime in a massive tax fraud scam.

Supporters claim that Magnitsky died after being severely beaten in prison, while officials said he died from acute heart failure and toxic shock, caused by untreated pancreatitis.

At the time of his death, Magnitsky was working for Hermitage Capital Management under Browder, an US-born hedge fund boss who was an alleged victim of the tax fraud scheme.

After the death, Browder launched an international campaign for justice to throw a spotlight on corruption in Russia.

The death soured relations between the US and Russia, with Washington imposing sanctions on several Russian officials in response while in Russia, while US officials were sanctioned and Magnitsky was posthumously put on trial in response.