<p>MOSCOW — Thousands of people streamed to a Moscow bridge overlooking the Kremlin on Saturday to lay flowers and mark the sixth anniversary of the killing of Boris Nemtsov, a top Russian opposition figure. </p>
<p>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. </p>
<p>Among those who attended Saturday’s commemoration was Yulia Navalnaya, the wife of imprisoned Russian opposition leader Alexei Navalny. </p>
<p>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. </p>
<p>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. </p>
<p>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. </p>
