Russian prosecutors launched on Tuesday a probe into the recent death in prison of a lawyer representing London-based hedge fund Hermitage Capital, a spokeswoman for the Russian Prosecutor General's Office said.

Sergei Magnitsky died last Monday at Moscow's Matrosskaya Tishina detention centre. Russian President Dmitry Medvedev ordered earlier in the day Prosecutor General Yury Chaika and Justice Minister Alexander Konovalov to conduct a probe into the incident.

"On presidential instructions, the Prosecutor General's Office is probing into the death of Sergei Magnitsky at a pre-trial detention center," Marina Gridneva said.

The Russian Prosecutor General's office said earlier that Magnitsky, who was 37, died of a heart attack.

Magnitsky's lawyer, Dmitry Kharitonov, said he had demanded that Magnitsky undergo a medical examination, but the Interior Ministry's investigative committee said Magnitsky had never voiced health complaints.

Magnitsky had been in jail since 2008 amid a tax dispute between the Russian authorities and Hermitage Capital, once the largest investment fund in Russia.

Hermitage co-founder Bill Browder is the subject of a tax evasion investigation, and the lawyer was charged with conspiracy in the case, which has not come to trial.

MOSCOW, November 24 (RIA Novosti)