article_snippet: (CNN)Slain Russian opposition figure
article_snippet: Boris Nemtsov had been arrested several times for speaking against Putin's government.
article_snippet: The most recent arrests were in 2011 when Boris Nemtsov protested the results of parliamentary elections and in 2012 when tens of thousands protested against Putin.
article_snippet: But critics of Putin have in the past suffered miserable fates.
article_snippet: last year, a Moscow court sentenced five men to prison for the killing.
article_snippet: Business magnate Mikhail Khodorkovsky accused Putin of corruption and spent 10 years in prison and labor camps.
article_snippet: Russian spy Alexander Litvinenko accused state security services of organizing a coup to put Putin in power.
article_snippet: Business magnate Mikhail Khodorkovsky was poisoned by a lethal dose of radioactive polonium and died in London in 2006.
highlights_snippet: Kremlin critic and opposition figure