(Bloomberg) -- Russia’s opposition blamed the government for creating the atmosphere that led to Boris Nemtsov’s slaying as world leaders called on President Vladimir Putin to ensure a thorough probe into one of the highest profile political assassinations since Putin came to power 15 years ago.....

“Of course the authorities are guilty,” Mikhail Kasyanov, a former prime minister and opposition leader, told Bloomberg. “The authorities are guilty because they don’t let citizens speak words of truth and use their constitutional rights to demonstrations, elections, to criticize the authorities.”
Nemtsov, a politician who rose to prominence in the rush of reform after the Soviet collapse and then fell out with Putin, was gunned down Friday night near the onion domes of St. Basil’s Cathedral and just steps away from the Kremlin ahead of a Sunday protest against Putin’s rule that Nemtsov helped organize. The rally will instead be a vigil running through the city center and ending at the location where he was killed.
Russia’s main criminal investigative committee said it was looking at several possible motives for the murder, including whether Nemtsov was used as a sacrificial lamb to destabilize the country or if Islamist extremists were behind it. Such theories didn’t convince Putin foes.
“I have talked to my acquaintances who worked in special services, and I have less and less doubt that the killing of Boris Nemtsov is backed by the authorities,” Vladimir Milov, a former deputy energy minister, said in a blog posting. “I understand all the voices like: ‘Putin couldn’t or it’s not in his interests and so on.’ But there are objective facts.”

Gunned Down

Nemtsov was gunned down around 11:15 p.m. local time Friday after a car approached him and fired several shots, four of which hit him in the back, according to Interior Ministry spokeswoman Elena Alekseeva. Authorities said today that they’ve found the vehicle they believe was used in the murder.
His killing comes as the U.S. and its European allies are locked in the tensest standoff with Russia since the Cold War. The U.S. and European Union, which imposed economic sanctions on Russia after Putin annexed the Crimea from Ukraine last year, accuse him of fomenting an armed separatist revolt in eastern Ukraine, a charge Putin denies.
Nemtsov had been getting death threats and was working on a report about Putin and Russia’s involvement in Ukraine’s civil war, according to Ilya Yashin, an opposition leader. In 2011, he published a report that focused on how the leader’s friends and relatives benefited from the regime and on the perks Putin enjoyed himself as the head of an oil-rich state.

Critics Murdered

Dmitry Peskov, the Russian leader’s spokesman, said that “the president noted that there are all the signs that this was a hit and also an extreme provocation.” Peskov said the government would thoroughly investigate “this cruel murder” and that it would be wrong to see this as the start of a string of political killings.
Other Putin critics who have been murdered in recent years include Alexander Litvinenko, a former Russian spy who died in London in 2006 after drinking radioactive tea, and Anna Politkovskaya, a journalist who chronicled corruption under Putin and human-rights abuses during Russia’s conflict with separatists in Chechnya, who was gunned down in 2006.
Muscovites today brought flowers to the bridge near which Nemtsov was shot and state television broadcast special programming on the killing. Anatoly Chubais, head of state-owned venture capital company OAO Rusnano and the mastermind of Russia’s first privatization program, was among those shown on television at the location of the murder.

Courageous

German Chancellor Angela Merkel is “dismayed” by Nemtsov’s murder and calls on Putin to ensure that the murder is fully investigated, Steffen Seibert, her chief spokesman, said in a statement.
U.S. President Barack Obama said in a statement: “I admired Nemtsov’s courageous dedication to the struggle against corruption in Russia and appreciated his willingness to share his candid views with me when we met in Moscow in 2009.”
Nemtsov, 55, rose to prominence in the 1990s as a pro-reform politician during the presidency of Boris Yeltsin shortly after the collapse of the Soviet Union.
Nemtsov was governor of Nizhny Novgorod, a region that was associated with early efforts to promote a market-oriented transformation of the Russian economy. He then went to Moscow to become a deputy prime minister under Yeltsin.
After Putin succeeded Yeltsin in late 1999, Nemtsov became a critic and a leader of the opposition movement.

Sidelined

Putin foes have struggled to gain traction as the government stepped up efforts to sideline them. Two key opposition leaders who helped plan the original anti-crisis rally for Sunday won’t even be able to attend. Alexey Navalny is serving a 15-day sentence for handing out leaflets at a metro station, while former Yukos Oil Co. chief Mikhail Khodorkovsky is outside the country in exile after being freed from a Russian prison.
Nemtsov also served as an adviser to former Ukrainian President Viktor Yushchenko, who was swept into power by that country’s 2004 Orange Revolution. Putin has frequently warned that those events could serve as a model for Russian anti-government activists.
Nemtsov was “one of not many I can call friend,” Ukrainian President Petro Poroshenko wrote on Facebook. “He was a bridge between Ukraine and Russia. It’s ruined by murderers, I think not incidentally.”
To contact the reporters on this story: Ilya Arkhipov in Moscow at iarkhipov@bloomberg.net; Yuliya Fedorinova in Moscow at yfedorinova@bloomberg.net
To contact the editors responsible for this story: Balazs Penz at bpenz@bloomberg.net Chad Thomas