Putin Critic Navalny Mourned After Mysterious Prison Death and Arrests of Hundreds
- Alexei Navalny was a prominent critic of Russian President Vladimir Putin
- Navalny died suddenly in prison in Russia's Arctic region on February 16
- His funeral service will be held on Friday at a Moscow cemetery
- Navalny's wife and world leaders have blamed Putin for his death
- Since Navalny's death, 400 people have been arrested in Russia for honoring him