Detailed Instructions: In this task, you are given a text of many news articles seperated by special token "|||||". Your task is to summarize them.
Problem:Opposition leader Boris Nemtsov speaks to the media during a gathering of opposition supporters in central Moscow March 17, 2012. 
  
 Medics carry the body of Boris Nemtsov, who was shot dead, in central Moscow February 28, 2015. 
  
 MOSCOW Boris Nemtsov, a Russian opposition politician and former deputy prime minister who was an outspoken critic of President Vladimir Putin, was shot dead meters from the Kremlin in central Moscow late on Friday. 
  
 Nemtsov, 55, was shot four times in the back, the Interior Ministry said. A police spokeswoman on the scene said he had been walking on a bridge over the Moskva River with a Ukrainian woman. 
  
 Putin condemned the killing and took the investigation under presidential command, saying it could have been a contract killing and a "provocation" on the eve of a big opposition protest that Nemtsov had been due to lead in Moscow on Sunday. 
  
 Police cars sealed off the bridge close to the red walls of the Kremlin and Red Square, and an ambulance was on the scene. 
  
 "Nemtsov B.E. died at 2340 hours as a result of four shots in the back," an Interior Ministry spokeswoman said by telephone. 
  
 A police spokesman on the scene said Nemtsov had been shot at from a passing white car that fled the scene. The woman was being interviewed by police. 
  
 Mikhail Kasyanov, a fellow opposition leader, told reporters at the bridge: "That a leader of the opposition could be shot beside the walls of the Kremlin is beyond imagination. There can be only one version: that he was shot for telling the truth." 
  
 Kasyanov, a former prime minister under Putin, called Nemtsov a "fighter for the truth". 
  
 OPPOSITION TO WAR IN UKRAINE 
  
 Nemtsov had been quoted as saying he was concerned that the president might want him dead over his opposition to the conflict in Ukraine. Sunday's opposition march is intended as a protest against the war in east Ukraine, where pro-Russian rebels have seized a swathe of territory. 
  
 Putin's spokesman, Dmitry Peskov, told Russian news agencies that the president had expressed his condolences and ordered the security agencies to investigate. He said Putin had called it a "brutal murder". 
  
 Another opposition figure, Ksenia Sobchak, said Nemtsov had been preparing a report on the presence of Russian troops in Ukraine. The Kremlin strongly denies allegations by Kiev and Western capitals that it has sent troops and advanced weaponry to back the rebels. 
  
 Peskov said Putin had called it a "brutal murder". 
  
 Like other opposition leaders, Nemtsov was a fighter against corruption. In other reports, he condemned massive overspending on the Sochi Winter Olympics by the Russian authorities and listed the many state buildings, helicopters and planes that Putin has at his disposal. 
  
 Nemtsov was also one of the leaders of mass rallies in the winter of 2011-12 that became the biggest protests against Putin since the former KGB spy rose to power in 2000. 
  
 Nemtsov briefly served as a deputy prime minister under president Boris Yeltsin in the late 1990s, when he gained a reputation as a leading liberal reformer. 
  
 (Reporting By Alexander Winning and Vladimir Soldatkin; Writing by Timothy Heritage; Editing by Kevin Liffey) ||||| Investigation is under way into the murder of Russian opposition politician Boris Nemtsov, as some blame President Vladimir Putin's administration. (Reuters) 
  
 Investigation is under way into the murder of Russian opposition politician Boris Nemtsov, as some blame President Vladimir Putin's administration. (Reuters) 
  
 Boris Nemtsov, a towering figure in Russian post-Soviet politics and a biting critic of President Vladimir Putin, was gunned down steps from the Kremlin late Friday, authorities said. The drive-by shooting had the potential to open a violent new chapter in Russian political life. 
  
 Nemtsov, a physicist-turned-politician who was seen in the 1990s as a possible heir to President Boris Yeltsin, was one of the loudest voices condemning Russia’s sharp turn toward confrontation with the West in the past year. The killing sent immediate shock waves through Russia, where he became the highest-profile opposition leader to be slain in a nation where such figures are sometimes imprisoned or pushed to emigrate. 
  
 There was no immediate information on who killed the 55-year-old politician as he walked across a central Moscow bridge shortly before midnight on an unusually warm winter’s night. Putin said it bore the marks of a contract killing intended to embarrass the Kremlin, a spokesman said. Opposition leaders said they were sure that it was an attempt to intimidate them. 
  
 The killing was a dramatic and bloody turn for Russia’s oppressed opposition movement, which has struggled to find its footing during a wave of nationalistic fervor unleashed by the annexation of Ukraine’s semi­autonomous Crimean region last year. Many leaders have been marginalized with prison terms or other forms of harassment, and public rhetoric has grown extremely aggressive toward those who deviate from the majority line. 
  
 The shooting came a day before a rally at which opposition leaders had been hoping to breathe fresh life into their cause. Nemtsov was one of the main organizers. 
  
 1 of 37 Full Screen Autoplay Close Feb. 28, 2015 Skip Ad × Russian opposition leader gunned down in the streets of Moscow View Photos Boris Nemtsov, who was among leaders planning an opposition rally for Sunday, was fatally shot on a bridge in the heart of Moscow. Caption Boris Nemtsov was fatally shot late Friday on a bridge in the heart of Moscow. March 1, 2015 Russia's opposition supporters carry a banner bearing a portrait of Kremlin critic Boris Nemtsov during a march in central Moscow. Alexander Utkin/AFP/Getty Images Buy Photo Wait 1 second to continue. 
  
 Politically motivated slayings are not unknown in Russia, but not once in the 24 years since the breakup of the Soviet Union has such a high-profile figure been the victim. Shaken opposition leaders said in the hours after Nemtsov’s slaying that they were newly fearful, but they vowed to carry on. It was not immediately clear whether they would hold the rally on Sunday. 
  
  
  
  
  
 Just hours before his death, Nemtsov told Ekho Moskvy radio that Putin had pushed Russia into an economic crisis through his “mad, aggressive and deadly policy of war against Ukraine.” 
  
 The killing took place as Nemtsov walked in the heart of Moscow across the Bolshoi Moskvoretsky Bridge, less than 100 yards from the walls of the Kremlin and within sight of Red Square, one of the most secure areas in all of Russia. Police and secret services­ have a heavy presence in the region. There was no word on whether Putin was in the Kremlin at the time; he typically sleeps at a presidential residence on the outskirts of Moscow. 
  
 “Nemtsov’s murder is a terrible tragedy for Russia,” said former finance minister Alexei Kudrin, one of the few Putin allies who is also publicly critical of him. 
  
 Nemtsov was a political star in the early post-Soviet days, when most Russians still dreamed of democracy — a young, energetic and smart politician who charmed voters and won high approval ratings as a regional governor and then as Russia’s deputy prime minister. For a time, he was seen as a likely heir to Yeltsin, who served from 1991 to 1999 as the first president of the Russian Federation. 
  
 Instead, Putin assumed the presidency in December 1999 and set about relentlessly marginalizing his opponents. He has held power in one capacity or another since then. 
  
 Nemtsov received a doctorate in physics in 1990 and then served as a lawmaker for three years. Yeltsin appointed him governor of Nizhny Novgorod province in 1991. 
  
 1 of 20 Full Screen Autoplay Close Skip Ad × The life and protests of Boris Nemtsov View Photos The sharp critic of Russian President Vladi­mir Putin was shot and killed in central Moscow, the Interior Ministry said early Saturday. Caption The Russian opposition leader was shot and killed in central Moscow, the Russian Interior Ministry said early Saturday. March 15, 2014 Boris Nemtsov addresses demonstrators during a rally in Moscow to oppose President Vladimir Putin’s policies in Ukraine. More than 10,000 people turned out to oppose what many called an invasion of the Crimean Peninsula. Alexander Zemlianichenko/AP Buy Photo Wait 1 second to continue. 
  
 He was a key architect of Russia’s no-holds-barred moves toward capitalism, instituting free-market economic policies and simplifying the nightmarish and corrupt processes of registering new businesses. 
  
 Nemtsov was so popular that the Yeltsin camp of reformers briefly considered running him for president in 1996, but nothing came of the effort. Nemtsov reluctantly accepted the office of first deputy prime minister after Yeltsin was reelected in 1997. 
  
 As deputy prime minister, Nemtsov spearheaded a program of economic “shock therapy” designed to haul Russia out of its post-Soviet doldrums. He sought to make bidding on government contracts more competitive and transparent. His efforts earned him the ire of Russia’s notorious oligarchs, the powerful businessmen who were accused of looting the nation’s assets after the fall of the Communist government. 
  
 More recently, Nemtsov had been working on a report that he said would prove that Russian soldiers were fighting alongside pro-Russian rebels in eastern Ukraine, where a bloody 11-month-conflict has claimed nearly 5,800 lives. The Kremlin has hotly denied any direct involvement, which Russian opinion polls suggest would be deeply unpopular. 
  
 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.” 
  
 Flashing police lights illuminated the night Saturday on the Bolshoi Moskvoretsky Bridge, which runs from the base of St. Basil’s Cathedral to an island in the Moscow River where major opposition rallies were held in 2011 and 2012. Nemtsov was shot four times, Interior Ministry spokeswoman Yelena Alexeeva told journalists at the scene. Authorities were questioning witnesses, including a Ukrainian woman with whom Nemtsov was walking across the bridge when he was shot, Alexeeva said. 
  
 Images broadcast after his slaying showed his body lying face-up on the sidewalk of the bridge as emergency personnel appeared to attend to him. 
  
 Putin quickly condemned the killing and said he was directing Russia’s top security officials to take personal charge of the investigation, a measure of the shock waves that it sent through the political establishment. 
  
 “Putin noted that this cruel murder has every sign of being a contract killing, which has a solely provocative nature,” Kremlin spokesman Dmitry Peskov told Russian news agencies. 
  
 Russian opposition leaders said Saturday that they were fearful that Nemtsov’s slaying was only the first in a new era of political repression. 
  
 “This murder, politically, it hits the spot, because if the message is to send a scare throughout the opposition movement, this is one thing to do,” said Vladimir Milov, an opposition leader who alongside Nemtsov had been planning the Sunday rally. 
  
 “Scared or not scared, we will carry on,” he said. 
  
 Milov said he did not think it would be the last killing of an opposition leader in Russia. 
  
 “This is a new level, but as sad as it may sound, we have to expect a continuation. Because this is just how Russia operates now,” he said. 
  
 In 2012, Putin warned publicly that his opponents were prepared to murder one of their own so they could blame him for the death. 
  
 “They are looking for a so-called sacrificial victim among some prominent figures,” Putin, a former KGB agent, told a gathering of the All-Russia Popular Front, a group organized to support him, ahead of Russia’s 2012 presidential election. “They will knock him off, I beg your pardon, and then blame the authorities for that.” 
  
 In comments that took on a new significance Saturday, Nemtsov said earlier this month that he was worried that Putin would have him killed. 
  
 “A bit” worried, Nemtsov told the Sobesednik magazine. “Not as much as my mother, but still.” 
  
 “If I were very fearful,” he said, “I probably wouldn’t head an opposition party. I probably wouldn’t be involved in what I do.” 
  
 Branigin reported from Washington. Kathy Lally in Washington and Natasha Abbakumova in Moscow contributed to this report. ||||| MOSCOW (AP) — Boris Nemtsov, a charismatic former deputy prime minister turned Russian opposition leader, was shot and killed in Moscow Saturday, officials said. He was 55. 
  
 FILE - In this file photo taken on Saturday, March 15, 2014, Boris Nemtsov, a former Russian deputy prime minister and opposition leader addresses demonstrators during a massive rally to oppose president... (Associated Press) 
  
 FILE - In this file photo taken on Thursday, May 30, 2013, Boris Nemtsov, a former Russian deputy prime minister and opposition leader, presents a report claiming widespread corruption during preparations... (Associated Press) 
  
 Nemtsov's death comes just a day before a planned protest against President Vladimir Putin's rule. The Kremlin said that Putin will personally oversee the investigation. 
  
 Nemtsov was a sharp critic of Putin, assailing 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. 
  
 The Russian Interior Ministry, which oversees Russia's police force, said that Nemtsov was shot four times from a passing car as he was walking a bridge just outside the Kremlin shortly after midnight. 
  
 Nemtsov served a deputy prime minister in the 1990s and once was seen as a possible successor to Boris Yeltsin, Russia's first elected president. After Putin was first elected in 2000, Nemtsov became one of the most vocal critics of his rule. He helped organize street protests and wrote extensively about official corruption. |||||
Solution:
One of Vladimir Putin's most vocal critics has been shot dead in Moscow—and guess who's taking personal charge of the investigation? The Kremlin says Putin himself will handle it, reports AP. Authorities say a gunman in a passing car shot Boris Nemtsov four times in the back as he walked near the Kremlin about midnight local time, reports Reuters. Nemtsov served as a deputy prime minister under Boris Yeltsin and had emerged in recent years as an opposition leader. Among other things, he has alleged corruption among Kremlin insiders and was to lead a rally in Moscow tomorrow. The Washington Post adds some strange context to the killing. A few years ago, Putin asserted that his opponents would murder one of their own so they could blame him for it. After he made the comments, Nemtsov himself called on Putin to prevent it. “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 told Interfax.