In this Sunday, Feb. 26, 2017 file photo, People gather in memory of opposition leader Boris Nemtsov, portrait in center, in St. Petersburg, Russia. Once deputy prime minister under Boris Yeltsin, Nemtsov was a popular politician and harsh critic of Putin. On a cold February night in 2015, he was gunned down by assailants on a bridge adjacent to the Kremlin as he walked with his girlfriend in a death that sent shockwaves across the country. (AP Photo/Dmitri Lovetsky, file)