Signs that read 'I am not afraid' are carried at a march in Moscow in memory of Boris Nemtsov. His killing has been compared to the murders of critical journalists. (Reuters/Sergei Karpukhin)
Signs that read 'I am not afraid' are carried at a march in Moscow in memory of Boris Nemtsov. His killing has been compared to the murders of critical journalists. (Reuters/Sergei Karpukhin)

Murder of Boris Nemtsov highlights Russia’s impunity record