MailOnLine... Politician Boris Nemtsov was killed in front of his girlfriend on Friday night The 55-year-old was a staunch critic of Vladimir Putin and his government Critics have assigned blame to the Russian President for Nemtsov's death Hundreds gathered at the site in central Moscow protesting 'je suis Boris' They claim the murder was an attack on free speech like Charlie Hebdo Putin described the killing as 'vile' and has taken control of investigation World leaders demanded transparency as inquiries into death continue Hundreds of protesters have gathered at the scene where Russian politician Boris Nemtsov was murdered to name Vladimir Putin as the culprit of his death.
Critics held up signs reading 'we are all Nemtsov' this afternoon to claim the 55-year-old had been murdered for openly criticising the Russian President in a similar attack on free speech to the Charlie Hebdo massacre.
Ukrainian President Petro Poroshenko has blamed the Kremlin for Mr Nemtsov's death, alleging politicians were afraid of a report the former deputy prime minister was due to share publicly.
The findings are said to link Russia to the Ukrainian crisis which has seen thousands of people slaughtered after separatist rebels and military forces clashed.
Among mounds of flowers and candles left on the bridge in central Moscow are signs reading 'Je suis Boris' and 'We are all Nemtsov' in Russian claiming the 55-year-old was killed for openly criticising Putin in an attack on free speech Nemtsov, 55, had been out for dinner with his Ukranian model girlfriend Anna Duritskaya
Speaking of the report Mr Nemtsov had been working on, President Poroshenko said: 'Somebody was afraid of this, Boris wasn't afraid. Killers and executors were afraid.'
Meanwhile opposition activists also blamed the Russian President for his death, claiming they were in 'no doubt' it was politically motivated.
'I have no doubt this was a political killing. The only threat to his life came from his political activity. He had no foes other than political ones.',' said Ilya Yashin.
On Saturday hundreds of people gathered to lay flowers and messages of support at the scene where he was killed after enjoying dinner with his 23-year-old girlfriend.
Among placards left on mounds of flowers were some reading 'je suis Boris', 'Putin killed my friend' and 'we are all Nemtsov'.
Critics linked his killing to the deaths of journalists at the French political magazine, Charlie Hebdo, who were slaughtered by Islamic extremists after publishing cartoons of the Prophet Mohammed.
In the days before his death, Mr Nemtsov, a former deputy prime minister, said he feared being killed by the Russian leader.
'I'm afraid Putin will kill me. I believe that he was the one who unleashed the war in the Ukraine. I couldn't dislike him more,' he said in an interview with Russia's Sobesednik news website.
He also revealed his 86-year-old mother's fears that he was be assassinated because of his outspoken views.
'"When will you stop cursing Putin? He'll kill you for that." She was completely serious,' he added.
A growing mound of flowers was left at the scene as mourners visited on Saturday. Critics have blamed the Russian President for Mr Nemtsov's death, alleging it was 'politically motivated' Russian investigators said it was following several lines of inquiry but world leaders have demanded transparency as the investigation into Mr Nemtsov's death continues
Mourners wept at the scene on Saturday after critics blamed the Russian President for the popular politician's murder The father-of-four was shot four times by assailants previously reported as having been in a white car as he walked across a bridge over the Moskva River
Ukrainian President Petro Poroshenko said he thought Mr Nemtsov was killed because of a report he had been working on which incriminated Putin The Russian President has described the murder of Boris Nemtsov as 'vile'
The white car (pictured) that carried the assassins has reportedly been found by police not far from where the leader was murdered. Footage released on Sunday suggested his shooter may have been on foot and driven away after the killing
Medics carry the body of Boris Nemtsov. The politician was highly critical of the government's inefficiency, rampant corruption and the Kremlin's policy on Ukraine, which has strained Russia-West ties to a degree unseen since Cold War times
She received a telegram from the Russian president which described her son's murder as 'vile and cynical'.
'We will do everything to ensure that the perpetrators of this vile and cynical crime and those who stand behind them are properly punished,' it said.
'Please accept my deepest condolences in connection with this irreparable loss. I sincerely share your sorrow.
'Boris Nemtsov has left his mark in the history of Russia, in its political and public life. He occupied significant posts in a difficult time of transition in this country. He always openly and honestly voiced and upheld his views.'
He has now assumed 'personal control' of the investigation and his spokesman Dmitry Peskov said the shooting could be a 'provocation' for the planned protest rally.
Chairman of the Human Rights Foundation and former chess champion Garry Kasparov last night tweeted: 'Devastated to hear of the brutal murder of my long-time opposition colleague Boris Nemtsov. Shot 4 times, once for each child he leaves.
'Boris's quality no longer fit Putin's Russia. He always believed Russia could change from inside without violence; after 2012, I disagreed.
'When we argued, Boris would tell me I was too hasty, that in Russia you had to live a long time to see change. Now he'll never see it. RIP.'
Journalist Anna Politkovskaya, also a critic of Putin, was shot dead in a lift in October 2006, and former KGB spy Alexander Litvinenko is thought to have been poisoned by Russians in London and died a month later.
Some also believe that Boris Berezovsky, the Russian oligarch and another critic of Putin, may have been murdered after he was found hanged in the bathroom of his Ascot home in March 2013.
Russia's Investigative Committee said it was following several lines of inquiry including the possibility someone from Mr Nemtsov's own party had carried out the killing in order to raise support for a forthcoming anti-government rally.
Investigators also said the 'meticulously planned' assassination may also have possible links to Ukraine events as well as Islamist extremist attacks.
But supporters of Mr Nemtsov maintained the Kremlin was to blame for his killing which came just days before he was due to attend the Spring March opposition protest.
Mikhail Kasyanov, a former Russian prime minister now also in opposition, said the country is 'rolling into the abyss'.
'In the 21st century, a leader of the opposition is being demonstratively shot just outside the walls of the Kremlin. This country is rolling into the abyss,' he said.
The car that carried the assassins has reportedly been found by police not far from where the leader was murdered, according to REN TV news channel.
Officers are investigating the car, which has allegedly been identified as a Lada Priora with registration plates from Ingushetia, a republic of Russia in the North Caucasus region.
Preliminary results show that the politician was killed from a Makarov pistol and experts found six 9-mm cartridge cases at the scene.
Mikhail Kirtsev, who arrived at the scene before police cordoned off the area, said there were bullet wounds in Mr Nemtsov's back, and one on the left side of his body, by his lower ribs.
'Maybe he had time to turn around,' Kirtsev said, adding that there was little visible blood.
The married father-of-four was shot four times by assailants in a white car as the couple walked across a bridge over the Moskva River Russian opposition leaders Ilya Yashin (left) and Ksenia Sobchak (right), arrive at the scene. They alleged he was killed for openly implicating Putin in the Ukrainian crisis
British Prime Minister David Cameron said the Russian opposition leader dedicated his life to speaking up for the Russian people
Western leaders have condemned the assassination of Russian opposition leader Boris Nemtsov are are pressing the Kremlin to ensure the killing is investigated thoroughly.
Ukraine's president, Petro O Poroshenko, wrote on his Facebook page that Mr. Nemtsov had been a 'bridge between Ukraine and Russia' and that the 'murderers' shot has destroyed it. I think this is not an accident.'
German Chancellor Angela Merkel said she 'appreciates the courage of the former deputy prime minister, who repeatedly expressed publicly his criticism of government policy.'
She called on Putin to ensure that the murder is cleared up and the perpetrators brought to justice.'
Canadian Prime Minister Stephen Harper said: 'Mr. Nemtsov will be remembered as a fearless advocate of democracy, human rights and the rule of law in Russia.
'A leader unafraid to voice essential truths, even in the face of violent intimidation, he was also a prominent opponent of Russia's aggression in Ukraine and the illegal occupation of Crimea.'
David Cameron said: 'Boris Nemtsov was a man of courage and conviction.
'His life was dedicated to speaking up tirelessly for the Russian people, to demanding their right to democracy and liberty under the rule of law, and to an end to corruption.
'He did so without fear, and never gave in to intimidation.'
French President Francois Hollande also denounced the 'odious assassination' of Boris Nemtsov in Moscow.
The killing came one year after the Russian annexation of Crimea in a special operation by Russian special forces. The politician was a strong and outspoken critic of Putin's policy on Ukraine.
Kiev, the West and some Russians accuse Moscow of sending troops to support separatist rebels who have risen up in east Ukraine, an accusation Russia has denied.
Just hours before the opposition leader's death Putin had declared 27 February a new 'professional holiday' for special operation soldiers in his armed forces and secret services.
Political analyst Sergey Parkhomenko alluding to this new holiday said that the murder was carefully planned and a 'present' for someone.
'There is a war going on here. If someone thinks otherwise... we're now living in a country that is fully-fledged in a war.'
'Nemtsov's murder is a terrible tragedy for Russia,' said ex-finance minister Alexei Kudrin, a Putin ally.
Prime Minister, David Cameron, said: 'I am shocked and sickened by the callous murder of Boris Nemtsov as he walked in the heart Moscow last night.
'This despicable act must be fully, rapidly and transparently investigated, and those responsible brought to justice.
'Boris Nemtsov is dead. But the values he stood for will never die.'
Ukrainian President Petro Poroshenko has said the politician may have been murdered because he planned to disclose evidence of Russia's involvement in Ukraine's separatist conflict.
'He said he would reveal persuasive evidence of the involvement of Russian armed forces in Ukraine. Someone was very afraid of this ... They killed him,' Poroshenko said.
US President Barack Obama has also condemned the 'brutal murder', the White House National Security Council said on Twitter.
The White House called on the Russian government to conduct a 'prompt, impartial and transparent investigation' and to 'ensure those responsible are brought to justice.'
Obama said he met Mr Nemtsov in Moscow in 2009 when the Russian was willing to 'share his candid views with me'.
'We offer our sincere condolences to his family and to the Russian people, who have lost one of the most dedicated and eloquent defenders of their rights,' he said.
Mr Nemtsov, 55, first gained an international profile after being spotted by former British premier Margaret Thatcher as a future leader of Russia, and she praised his market reforms after visiting Nizhny Novgorod where as governor in the early 1990s he led spearheaded reforms.
Later he rose to become deputy prime minister under Boris Yeltsin, but he was always opposed as too Western and liberal by hardliners.
He had angered the government two years ago when he charged that billions of dollars had been stolen from funds designated for the 2014 Winter Olympics in Sochi, his home town.
He blamed 'Putin's friends' for the alleged embezzlement, which he described as 'a real threat to Russia's national security.'
Putin's former premier Mikhail Kasyanov, now an opposition leader, said: 'The comments are very easy: the bastards.
'They killed my friend in Moscow city centre, near the Kremlin wall.'
Mr Nemtsov had publicly expressed concerns for his life earlier this month and was outspoken in his opposition to Putin, pictured at a media rally in Moscow in 2012 '
Former Soviet President Mikhail Gorbachev warned against jumping to conclusions.
'Certain forces will try to use the killing to their own advantage. They are thinking how to get rid of Putin,' he said.
Another key opposition figure Vladimir Ryzhkov said: 'I'm absolutely shocked. It's the first case of political murder in many years, a slaying of a politician of federal level.'
He said the killing was an 'extraordinary, shocking event' and that 'political responsibility for what happened is with the authorities.'
Mr Nemtsov had publicly expressed concerns for his life earlier this month and was outspoken in his opposition to Putin.
He was highly critical of the government's inefficiency, rampant corruption and the Kremlin's policy on Ukraine, which has strained Russia-West ties to a degree unseen since Cold War times.
He helped organise street protests and wrote extensively about official corruption. He had been due to take part on Sunday in the first big opposition protest in months in the Russian capital.
The assassination also comes after Mr Nemtsov criticised Putin in the Financial Times on Thursday.
The politician had said residents he met in a town northeast of Moscow had complained about the country's economic problems.
He added: 'They believed that the embargo on imported foods is America's fault, and they were surprised when I told them no, that was not Obama, it was Putin.
'This is what we need to make people aware of: the crisis, that's Putin.' BORIS NEMTSOV: A LIBERAL REFORMER AND FIERCE PUTIN CRITIC
His 87-year-old mother Dina had a premonition that her son would be killed, according to the politician.
He told earlier this month how his mother warned him: 'When will you stop cursing Putin? He'll kill you for that.'
Nemtsov studied physics at State University of Gorky and earned a PhD in Physics and Mathematics.
In the wake of the Chernobyl disaster, Nemtsov organised a protest movement in his hometown, which prevented the construction of a new nuclear power plant in the region.
The liberal reformer rose to prominence under Boris Yeltsin and became a fierce critic of Vladimir Putin.
Nemtsov first gained an international profile after being spotted by former British premier Margaret Thatcher as a future leader of Russia.
She praised his market reforms after visiting Nizhny Novgorod where as governor in the early 1990s he led spearheaded reforms.
The father-of-four, 55, was Deputy Prime Minister of Russia from 1997 to 1998 during Boris Yeltsin's presidency.
He was sentenced to 15 days in jail in January 2011 after being arrested at a New Year's Eve protest rally for 'disobedience towards police'.
The politician founded a number of opposition movements after leaving the Russian parliament in 2003 and he had served as the co-chair of the opposition Republican Party of Russia - People's Freedom Party since 2012.
He was a prominent and vocal critic of Mr Putin and wrote a number of reports in recent years linking Putin and his inner circle to corruption.
It has been reported that Nemtsov angered Putin's government two years ago when he charged that billions of dollars had been stolen from funds designated for the 2014 Winter Olympics in Sochi, his hometown.
He has written more than 60 academic publications about quantum physics, thermodynamics and acoustics and designed n of antennas for space apparatuses.
Jewish advocacy website AJC named Nemtsov as one of the most prominent Jews in Russia thanks to his mother's heritage.
In his 1997 memoir, The Provincial Man, Nemtsov revealed that he was baptised Russian Orthodox in secret.
He leaves behind his wife Raisa Akhmetovna and four children.
The former research officer of the Gorky Radiophysical Research Institute with his daughter Zhanna in 1986
Nemtsov studied physics at State University of Gorky and earned a PhD in Physics and Mathematics, pictured during his time studying
Nemtsov studied physics at State University of Gorky and earned a PhD in Physics and Mathematics, pictured during his time studying
The murdered politician was known as an economic reformer during his time as governor of one of Russia's biggest cities, Nizhny Novgorod.
Political analyst Stanislav Belkovsky told the radio station that he did not believe that Mr Nemtsov's death would in any way serve Putin's interests.
'But the atmosphere of hatred towards alternative thinkers that has formed over the past year, since the annexation of Crimea, may have played its role,' he said, referring to the surge of intense and officially endorsed nationalist discourse increasingly prevalent in Russia since it annexed Ukraine's Crimean Peninsula.
One of Russia's most prominent opposition leaders, he was among 68 people arrested at an unsanctioned rally at a central Moscow square.
He was sentenced for failure to follow police orders, the state news agency RIA Novosti reported at the time.
A year ago, Putin had predicted a high profile opposition killing, claiming his deeply divided foes would kill on of their own number.
'They are looking for a so-called sacrificial victim among some prominent figures,' said Putin. 'They will knock him off, I beg your pardon, and then blame the authorities for that.'
Nemtsov hit back at Putin for the statement, declaring:
'If the head of the federal government, who controls all intelligence agencies, makes a public statement that he has information about such a provocation and such a crime, he must do everything to prevent it and not just publicly scare Russians.'
He warned: 'If the authorities fail to do everything to prevent such a scenario,' Nemtsov said then, 'they will become accomplices in this grave crime being plotted.'
Nemtsov had accused Putin of turning Russia back to the Cold War.
Boris Nemtsov gives radio interview hours before murder
'He believes that everything he did was absolutely right... he is not critical about himself at all. He says that he is right and the world is wrong. Sometimes I believe that he is mad,' he said.
When he died he was allegedly preparing to reveal evidence in a report entitled 'Putin, War' of Russia's direct involvement in the Ukrainian crisis.
Sergei Mitrokhin, leader of the opposition Yabloko party, called the killing an 'act of political terrorism'.
'This is a challenge not just to the opposition but to the leadership of the country.'
Nemtsov will be buried at Troyekurovskoye Cemetery in Moscow on March 3.
Amnesty International said the case must not be allowed to be added to a 'list of unsolved political murders and attacks' in Russia.
Deputy director for Europe and Central Asia Denis Krivosheev said: 'Boris Nemtsov was one of Russia's most prominent and courageous political activists and was a prisoner of conscience in the past when he was arrested in connection with peaceful street protest.
'He was, with others, actively planning a large opposition demonstration in Moscow on Sunday.
'In the current crackdown on freedoms of expression, assembly and association, this is a cold-blooded murder of one of those free voices whom the authorities have so actively sought to silence