MOSCOW, Oct 7, 2008 (AFP) - Four men will go on trial in a military court on October 15 in connection with the murder of Russian investigative reporter Anna Politkovskaya, a court spokesman said on Tuesday, news agencies reported.

'Today the Moscow District Military Court set a date for the preliminary hearing in the criminal case against Pavel Ryaguzov, Sergei Khadzhikurbanov and the Makhmudov brothers,' spokesman Alexander Minchanovsky was quoted by Interfax as saying on Tuesday's anniversary of the killing.

'The hearing will take place October 15,' he said.

Three men -- Khadzhikurbanov, a former officer in a Moscow police organised crime unit, and brothers Dzhabrail and Ibragim Makhmudov -- are charged with helping the gunman, who remains at large.

The fourth man on trial is Pavel Ryaguzov, a former officer in the FSB secret service, who was initially named as a murder suspect until prosecutors changed the charges against him to extortion and abuse of power.

His former FSB membership means that all four will be tried in a military court, which critics fear could mean the trial being closed to the public.

Politkovskaya, a Kremlin critic who exposed human rights violations in Chechnya, was gunned down outside her Moscow apartment on October 7, 2006, sparking outraging among Western governments and the Russian opposition.

About 200 of her supporters gathered in Moscow on Tuesday to mark the second anniversary of her killing.