A Russian court has issued an international arrest warrant for Mikhail Khodorkovsky, former Yukos Oil chief and critic of Russian President Vladimir Putin.
Russian police accuse Khodorkovsky, who is now based in London, of ordering the killing of the mayor of a Siberian oil town.
Khodorkovsky denies the charges. On Wednesday he said via social media that the charges are a response to his pro-democracy work.
The businessman was arrested in 2003 and convicted of tax evasion and fraud. Khodorkovsky says those charges -- which resulted in a decade in prison -- were motivated by his financial support of the political opposition.
Since his release in 2013, Khodorkovsky has lived in exile and founded a pro-democracy movement called Open Russia, aimed at Russian political reform.
Khodorkovsky was accused Wednesday of ordering the murder of Vladimir Petukhov, mayor of the town of Nefteyugansk, for financial gain. On Tuesday, Russian police raided some Moscow locations linked to Open Russia.