Why was Boris Nemtsov shot dead? The committee investigating the chilling murder of the vocal Kremlin critic within view of its red brick walls has already established a number of possible motives.
Among them is his outspoken opposition to the fighting in Ukraine.
- Conflicting reports of CCTV footage in Nemtsov investigation
- Russian propaganda stokes anti-West sentiment
For Nemtsov, a long-time opposition leader briefly considered as a possible successor to Boris Yeltsin until Vladimir Putin edged him out, the war next door had become a central, electrifying issue among a litany of complaints against Putin's leadership.
And Nemtsov was adamant about documenting proof that the Russian president is sending troops into Ukraine's churning conflict.
According to his friends, including the Ukrainian President Petro Poroshenko, Nemtsov was on the verge of disclosing new information in a document he was to call "Putin and the war."
"Boris had declared that he would provide the clear evidence of Russian armed forces' participation … in Ukraine," said Poroshenko following Nemtsov's shooting.
"Somebody was afraid of this, Boris wasn't afraid. Killers and executioners were afraid."
A dangerous conversation
Russia has consistently denied stoking the Ukraine conflict, or feeding it with men and materiel — despite mounting evidence, mostly produced abroad, to the contrary.
But while Russia's involvement is a subject often discussed outside Russia, inside, it is a difficult — even dangerous — conversation to have.
The rumours have been swirling for months. Russian mothers reporting their enlisted sons calling from inside Ukraine, many others reporting their sons missing.
In recent months, independent media have begun reporting on the whispers of Russian casualties secretly buried near the border.
But what discussion there is inside Russia about all this has lacked hard proof, though there have been some in Russia, in addition to Nemtsov, trying to find it.
But how do you prove a country is engaged in war if it won't acknowledge it?
A few months ago, a group of Russian journalists tried by investigating reports of secret soldier burials. They found at least one grave, before thugs scared them off — an act of intimidation the journalists caught on camera.
"They [were] very aggressive," Vladimir, the young videographer who filmed the attack for the independent Rain TV, told CBC News on a recent visit to Moscow.
"Some people don't want this information [to go] to the world. They don't want that people know."
Another opposition figure says he was brutishly beaten for asking similar questions.
Lev Shlosberg ended up in hospital last August after three men assaulted him, leaving him with serious head injuries.
He believes the attack had everything to do with his investigation into the deaths of paratroopers from his home in Pskov. He had attended a secret funeral held for one of them, and is certain they all died fighting in Ukraine.
Kept from view
Russia insists any of its men fighting on the rebel side of the conflict in eastern Ukraine are volunteers fighting of their own volition.
But last fall, journalists at Rain TV's website edition began compiling a list of Russian soldiers confirmed either missing in action or dead. In most of the cases, the journalists say, relatives were told the soldiers died during "exercises" "on the border" with Ukraine.
The journalists spent considerable time to confirm each case, to ensure they had the information right.
But most Russians, who largely watch state television, aren't exposed to that view, and certainly not to any of the data from Western sources, including NATO, said to show Russian involvement in Ukraine.
Even amidst the wall-to-wall coverage of the Ukraine conflict on Russian television, they aren't likely to have seen an exhibit mounted in Kyiv last weekend of a mountain of Russian hardware, including grenade launchers and drones, that were apparently seized in eastern Ukraine by government forces.
And the vast majority would not have attended the protest Nemtsov was to lead on Sunday, which he planned partly to amplify the criticism of Russia's policy in Ukraine.
"If you support stopping Russia's war with Ukraine, if you support stopping Putin's aggression, come to the Spring March," he wrote in a blog linked to his final tweet.
'I am not afraid'
What kind of proof did Nemtsov have? And is that the reason he was silenced? Though the answer isn't known — and may never be — in a sense, that may be beside the point.
Because Russia's most brazen political assassination in years silences a potent critic of the Kremlin, and strikes fear into anyone else trying to get at the truth — notwithstanding the posters asserting otherwise at Sunday's rally.
"I am not afraid," was a common slogan at the gathering.
But friends say even Nemtsov was concerned for his own safety. He said as much in an interview earlier this month when he said "I'm afraid Putin will kill me."
Was it Putin, as his critics allege, via someone acting on his behalf? Or as others have suggested, was it nationalists who believed Nemtsov, as a Putin critic, was a traitor? And if so, was killing him the best way to manage the problem?
A killing like this wouldn’t be the first in a country that is no stranger to violence and intimidation in pursuit of political goals.
The journalists at Rain TV weren't dissuaded by the intimidation they faced, but they were also very concerned their work would eventually land them in trouble.
"We don't get any response, and it's scary in a way," the web edition's editor in chief Ilya Klishin told CBC last fall.
"I don't know what is going to happen. We've got to do what we've got to do."