Russia hunts for killers of opposition figure Boris Nemtsov

Moscow: Russian investigators scrambled Monday to track down the killers of outspoken opposition figure Boris Nemtsov as fresh details emerged about the most shocking political assassination of Vladimir Putin's rule. The 55-year-old former deputy prime minister, a longtime Putin critic and renowned anti-corruption crusader, was shot dead shortly before midnight Friday while walking across a bridge just a short distance from the Kremlin.

Shocked opposition figures in Russia and Western leaders called for a full and transparent probe into the murder of Nemtsov, who served as Boris Yeltsin's deputy prime minister in the 1990s. On Sunday, about 70,000 people joined a memorial march in Moscow for Nemtsov, numbers not seen since the mass anti-Putin rallies of 2011 and 2012.

Putin himself vowed to spare no effort to bring the killers to justice, ordering law enforcement chiefs to personally take on the case. A reward of three million rubles ($48,000) is on offer for information on Nemtsov's death, a substantial amount in a country where the average monthly salary is 60,000 rubles ($960).

Various motives for the murder have been floated, including Nemtsov's opposition to Russia's role in the Ukraine conflict, as well as his condemnation of January's killings at the Charlie Hebdo satirical weekly in Paris by Islamist gunmen. It was also suggested the killers wanted to destabilise Russia, which is facing its worst standoff with the West since the Cold War over Ukraine.

As fresh details of the crime emerged in Russian media, however, there were suggestions the assassination may have been the work of low-level criminals, rather than a "meticulously planned" murder by professional hit-men as originally believed.

"Participants in the investigation are only sure of one thing that the killers were not professionals," said Kommersant business daily.

It said they used ammunition that was years old and possibly an unreliable home-made weapon. The murderer or murderers fired four bullets into Nemtsov's back as he was walking with Ukrainian model Ganna Duritska, and several more were found at the scene. The bullets were made by a variety of different manufacturers, the oldest dating back to 1986, Kommersant said, citing sources.

It quoted a law enforcement source as saying the killers appeared to have "collected together (the bullets) from all their pockets," suggesting poorly-armed second-rate criminals. The weapon may have been a Makarov pistol of the type used by Russian armed forces, or an easily-acquired Izh gas pistol, converted to fire live rounds, Kommersant reported.

A converted weapon of this type was used in 2006 to kill journalist Anna Politkovskaya, the Kremlin critic shot in her entranceway in a contract hit which has never been elucidated.

The senior investigator in charge of the probe was named as Igor Krasnov, known for solving high-profile crimes  committed by far-right nationalists, including the daylight shooting of rights lawyer Stanislav Markelov in 2009.

Nemtsov however was not a known target for nationalists, who have "kill lists". But he had received numerous death threats. Investigators first said the killer fired from inside a car, but witness statements later established he walked up steps onto the bridge and fled in a light-coloured car.

He was around 1.70 metres tall (five foot seven) with short dark hair, wearing blue jeans and a brown sweater, Life News website reported, citing a law enforcement source. But many questioned how a murder could be committed in one of the most secure places in Moscow and how the killer could escape. Nemtsov died just metres from Kremlin walls bristling with security cameras, yet cameras in the area reportedly gave unclear recordings or were broken.

Fellow opposition leader Alexei Navalny said Nemtsov would almost certainly have been under some form of surveillance at the time of his death, given the two had been planning a major rally in Moscow on Sunday.

Speculation also centred on the testimony of Duritska, the 23-year-old Ukrainian model at Nemtsov's side when he died, but who was not injured. She was walking home with him after they dined at the upmarket Bosco Cafe overlooking Red Square, Kommersant reported.

Nemtsov had just given a live interview on Echo of Moscow popular opposition radio station where he urged listeners to the Sunday opposition rally called to demand an end to the war in Ukraine. Nemtsov had a car with a driver waiting but the couple decided to walk the short distance to his flat despite icy rain, Life News reported, citing law enforcement sources. The website said Duritska, who has protested that she has been blocked from leaving Russia, helped draw up a photofit of the killer during a long interrogation.