Politkovskaya was well known for her opposition to the Chechen conflict and criticism of Vladimir Putin [AFP]
Russia has arrested Rustam Makhmudov, the suspected assassin of journalist Anna Politkovskaya, who was shot dead in 2006, federal investigators said.
Makhmudov was detained on Monday night in Chechnya at the home of his parents after being on the run for years, Russia's federal investigative committee announced on Tuesday.
Makhmudov's brothers, Dzhabrail and Ibragim, and former police officer Sergei Khadzhikurbanov have been investigated for several years over suspected involvement in the killing.
All three were acquitted on a lack of evidence in a jury trial in 2009, but the verdict was annulled by the supreme court and a new investigation reopened with the same suspects.
Politkovskaya, a 48-year-old mother of two who published damning exposes of official corruption and rights abuses, was shot dead in the stairwell of her Moscow apartment on October 7 2006.
Reporting on abuses
Renowned for her opposition to the Chechen conflict, Politkovskaya also reported on the alleged human rights abuses of Russian military forces under the leadership of former Russian president Vladimir Putin. She also covered alleged abuses by Chechen rebels and the current Moscow-backed administration led by the Kadyrov family in Chechnya.
Her death came as her reporting was increasingly being seen as a threat to the Chechen government, which has been accused of the rampant torture, abduction and murder of opposition figures.
"The biggest question is not who performed the murder, but who ordered it"
Dmitry Babich, RIA Novosti journalist
Politkovskaya wrote several books about the Chechen wars, as well as Putin's Russia - in which she accused Russian secret services of repressing civil liberties to re-establish a Soviet-style dictatorship.
Politkovskaya received numerous prestigious international awards for her work and her murder was widely perceived as a contract killing, sparking a strong international reaction.
Dmitry Babich, a political analyst and journalist for the Russian International News Agency, or RIA Novosti, told Al Jazeera that Politkovskaya's colleagues at Novaya Gazeta, a Russian opposition newspaper, belief that Makhmudov is likely guilty of her killing.
"So the biggest question is not who performed the murder, but who ordered it," Babich said.
"You know that Novaya Gazeta is very much in opposition to the Russian government, so they suspect someone from the current leadership of Chechnya (which is pro-Moscow) is behind the assassination.
"The relatives of Politkovskaya and other fellow journalists agree that these two brothers were tracking her movements on the day she was killed. They were suspected of actually giving the signal to the killer who was waiting inside her (apartment) building."