Rights activists and acquaintances of Russian investigative journalist Anna Politkovskaya are marking four years since her murder in the Russian capital.
Politkovskaya, a critic of then-President Vladimir Putin and his policies in Chechnya, was shot outside her Moscow apartment in what supporters claim was a contract killing.
Criticized for its handling of the case, Russia's chief investigator's office say they have launched a worldwide search -- with the help of Interpol, among others -- for the suspected killer, Rustam Makhmudov.
Russia also says it is extending its probe until February.
Russian rights activists say the lack of progress in the probe proves such murders can be committed with impunity in Russia, where a number of high-profile murders of rights activists and journalists have gone unsolved.
compiled from agency reports