More than 400 people have reportedly been detained in Russia for publicly mourning the death of Alexei Navalny, who died in an Arctic penal colony on Friday at age 47. He was the most prominent critic of Vladimir Putin in Russia and was serving a 19-year sentence at the time of his death on “extremism” charges. U.S. President Joe Biden and other Western leaders directly have blamed Putin for Navalny’s death. Prison authorities say Navalny died of “sudden death syndrome,” but his family has not yet been given access to his body to allow for an independent autopsy. For more, we speak with Russian American writer Masha Gessen, who charts Navalny’s political evolution from an ethnonationalist libertarian tapping into “xenophobic discontent” to an anti-corruption activist promoting a vision of civic nationalism. “I have no doubt … that he was killed,” says Gessen. “Putin was determined to see Navalny die in prison.”