Tens of thousands of people are set to march in Moscow to honor opposition leader Boris Nemtsov, who was shot dead on February 27.
Boris Nemtsov was due to lead an opposition march on March 1 but his supporters will now be marching to mourn his death.
President Vladimir Putin condemned Boris Nemtsov’s murder as “vile and cynical” and vowed to find the killers.
Boris Nemtsov’s allies call it a political killing linked to his opposition to Vladimir Putin and the Ukraine conflict.
Opposition supporters are due to gather in central Moscow at 14:00 local time on March 1, before marching to the spot on Great Moskvoretsky Bridge where Boris Nemtsov was killed.
Moscow city authorities had previously approved a march for up to 50,000 people but organizers said more people might now attend following the murder.
As night fell on February 28, flowers were piled up a meter high and two meters wide on the bridge.
Placards read: “We are all Nemtsov” and “Je Suis Boris” – the latter a reference to the Je Suis Charlie messages of support following the Charlie Hebdo killings in Paris in January.
Russia’s Investigative Committee said it was looking into a number of possible motives, including Boris Nemtsov’s opposition to the Ukraine war, his political and personal life, Islamic extremism or an attempt to destabilize the state.
A number of pro-government figures suggested Boris Nemtsov had been made a sacrificial victim to show the state in a bad light.
Ramzan Kadyrov, the Putin-backed leader of Chechnya, blamed: “Western special services, trying by any means to create internal conflict in Russia.”
Presidential spokesman Dmitry Peskov said Vladimir Putin had noted “that this cruel murder has all the makings of a contract hit and is extremely provocative”.
Others suggested there could have been personal enmity over Boris Nemtsov’s private or business life.
Boris Nemtsov was reportedly preparing documents on Russian military involvement in Ukraine in the weeks before his death.
Ukrainian President Petro Poroshenko said: “Boris had declared he would provide clear evidence of Russian armed forces’ participation in [the war] in Ukraine. Somebody was afraid of this… They killed him.”
Boris Nemtsov, 55, had been dining at a restaurant with his girlfriend Anna Duritskaya on Friday night.
They left together to walk to his flat, crossing the bridge, where a white car drew up and Boris Nemtsov was shot four times with a pistol at around 23:40.
Footage on Russian TV showed a white Lada Priora car in the area but there was no confirmation it was the one involved. One shot showed someone running along the road and jumping into the waiting car, which sped off.
Boris Nemtsov served as first deputy prime minister under President Boris Yeltsin in the 1990s but fell out of favor with Vladimir Putin and became an outspoken opponent.
He told the weekly Sobesednik recently that his mother was worried about him.
“She is more worried about Putin than Ukraine. Every time I call her, she gives me a talking-to: <<When will you stop being rude about Putin? He’ll kill you>>.”
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