Five Men Who Killed Putin Foe Boris Nemtsov Are Sentenced in Russiabr Investigators and allies of Mr. Nemtsov have long suspectedbr that Mr. Kadyrov may have been involved in the killing, but it remains unclear why he might have wanted Mr. Nemtsov dead.br Mr. Dadayev, who served as an officer in the security services of the Kremlin-backed Chechen leader, Ramzan A. Kadyrov, may have been the one who fatally shot Mr. Nemtsov, but the politician’s family and his supporters contendbr that the people who ordered the killing remain at large.br The shooting of Mr. Nemtsov, a charismatic opposition leader who antagonized the Kremlin, ended his two-decade democratic crusadebr that began in the wake of the Soviet Union’s collapse in 1991, and continued through the authoritarian rise of Mr. Putin.br His efforts drew the ire of Putin loyalists: The state-controlled news mediabr and Kremlin supporters called Mr. Nemtsov corrupt and a traitor, and spread propaganda to undermine his popular appeal.br Shortly before midnight on Feb. 27, 2015, the opposition leader Boris Y. Nemtsov was gunned down a few steps away from the Kremlin as hebr and his girlfriend were walking home across a bridge from Red Square.br Others have said he wanted to help his patron, Mr. Putin, by eliminating one of thebr Russian leader’s harshest critics, even though the killing embarrassed the Kremlin.