3 March 2015
Last updated at 00:34
In the absence of any arrest or claim of responsibility, there are multiple theories for the murder of Russian opposition politician Boris Nemtsov.
Was he killed because he opposed the policies of President Vladimir Putin and Russia’s alleged covert war in Ukraine?
Was he cut down in full view of the Kremlin in an attempt to discredit Russia’s leaders or even intimidate them, or incite a rebellion against them?
Perhaps it was an opportunistic attack by someone harbouring a grudge?
Here we look at some of the principal lines of inquiry.
Was it Putin?
“Illogical” and “unacceptable” is how Mr Putin’s spokesman, Dmitry Peskov, described this allegation when contacted by the BBC.
On the face of it, Nemtsov was a well-known, media-friendly, veteran opposition politician who was just days from leading an anti-war rally in Moscow (cancelled after his death).
“If you support stopping Russia’s war with Ukraine, if you support stopping Putin’s aggression, come to the Spring March in Maryino [a Moscow suburb] on 1 March,” he wrote in a social media post, published hours before he was shot (in Russian).
According to Ukrainian President Petro Poroshenko, Nemtsov was planning to publish “some persuasive evidence about the involvement of Russian armed forces in Ukraine”.
Such activities were bound to antagonise the Kremlin (as well as Russian nationalists backing the rebel cause in Ukraine, of course).
Yet even if you accept the possibility that the Kremlin might murder dissidents, the question remains: why kill Nemtsov and not other, younger, much more dangerous opposition figures such as Alexei Navalny?
Multiple, dubious corruption prosecutions have beset Mr Navalny since he mounted arguably the most serious challenge ever to Mr Putin’s rule, from the streets of Moscow in the winter of 2011-12.
During those same protests, Nemtsov played a minor role, jeered at times when he took to the stage alongside other opposition figures.
If the court proceedings against Mr Navalny were politically motivated, as many assume they were, where is the logic in killing a minor irritant but only gagging a real opponent?
Could Russian rogue elements have been at work?
The security services already enjoy massive power under President Putin, whose own popularity rating increased last month to 86%, according to one poll.
It seems unlikely that some sections might have planned the killing in order to justify some draconian new crackdown.
But why, on a bridge just outside the Kremlin walls covered by numerous security cameras, has no distinct footage emerged of the killers?
Could Russian ultra-nationalists with connections to the security services have had Nemtsov the pacifist, and labelled a traitor by some, killed as a warning to Mr Putin not to back down in the conflict over Ukraine?
A ceasefire the Russian president personally helped to negotiate last month finally seems to be taking hold in the conflict zone.
Was it Putin’s enemies?
Condemning Nemtsov’s “vile and cynical murder”, the Russian president vowed to bring to justice its organisers and perpetrators. It “had all the hallmarks of a contract killing” and was “entirely provocative in nature”, he said.
The clear implication here is that Mr Putin, at least in public, regards the killing as an organised assassination, not a random shooting in the street.
“Provocation” is Kremlin code for an attack aimed at destabilising the Russian state. As to who might be behind such an attack, the Kremlin’s “chief spin doctor”, TV anchorman Dmitry Kiselev, made clear who he thought stood to benefit most.
“When he was alive, Nemtsov was no longer necessary to the West, he had no prospects,” he said. “But dead, he was a lot more interesting.”
Following this Russian state TV scenario, if some foreign intelligence agency did indeed organise the assassination of Nemtsov to undermine President Putin, it appears to have miscalculated.
Some 50,000 people turned out to protest at his death on Sunday – a fair-sized crowd but nothing like the anti-government protests of 2011-12 – and there was no significant disorder.
- Gunman fired into Nemtsov from behind with a pistol as he walked across a bridge below the Kremlin hand in hand with a young woman
- Killer then jumped over the barrier into the road and got into a waiting car, which looked like a Russian vehicle, a witness called Viktor told pro-Kremlin Russian news website LifeNews (in Russian)
- A police source told LifeNews the gunman was around 1.7m (five foot seven) tall with short dark hair, wearing blue jeans and a brown sweater
- Nemtsov’s walking companion, Anna Durytska, saw a light-coloured car speeding off
- A police source told Russian daily Kommersant old bullets were used, possibly fired from a homemade gun. “Participants in the investigation are only sure of one thing – that the killers were not professionals,” the source said
Who hated Nemtsov enough to kill him?
Undoubtedly, there were Russians who hated Nemtsov for his liberal brand of politics and opposition to the war, seen as a sacred cause by many nationalists.
“It is no secret that there are some very radical characters among both sides in the conflict [over Ukraine], who are not subordinated to any authorities,” said Vladimir Markin, spokesman for Russia’s powerful Investigative Committee.
“So who’s Nemtsov?” asked one Moscow tweeter. “So much fuss while children and old people perish in Donetsk [eastern Ukraine] each day. Who remembers them?”
One common extreme reaction circulating on Russian-language social media was, “A dog’s death for a dog.”
If the killers’ idea (it appears there were at least two, in a car) was to confront Nemtsov, however, why shoot him in the back?
Another theory advanced by the Investigative Committee (often accused of political bias itself) is that the killers might have been Islamist extremists enraged by his condemnation of the Charlie Hebdo massacre in Paris.
Nemtsov, a famously outspoken politician, made no secret of his Jewish extraction though he was a baptised Christian. But again, where is the credible claim of responsibility?
Nemtsov had been involved in a well-publicised anti-corruption campaign in Yaroslavl, a provincial town not far from Moscow, and he also had a number of business interests.
Contract murders for commercial reasons have become less common in Moscow under Vladimir Putin but do still occur. However, the killers were taking a massive risk attacking Nemtsov in one of the most heavily guarded areas of Moscow.
What of the late politician’s love life? Even admirers used the epithet “womaniser” in regard to him.
However, the Ukrainian model less than half his age (he was 55) who was with him when he was shot on Friday night could say little about the attack.
Anna Durytska, who was unhurt, told Russian media she had not seen the killer, who had struck from behind. All she had seen, she said, was a light-coloured car which quickly drove off. Into the dark.