Nemtsov, 55, a former deputy prime minister, was shot to death as he walked along the Bolshoi Moskvoretsky bridge late at night on Feb. 27, 2015.
Navalny's detention in January upon returning to Moscow from five months of recuperating in Germany from a nerve-agent poisoning set off a wave of nationwide protests.
Nemtsov was one of Russia’s most energetic and charismatic opposition figures, and his death was a blow to political opponents of President Vladimir Putin.
An officer in the security forces of Chechnya’s Kremlin-backed leader was sentenced to 20 years for firing the shots that killed Nemtsov. Four other men were sentenced to 11 to 19 years for involvement.