Berlin CNN  — 

For years Leonid Volkov has experienced the same terrifying dream about his best friend and colleague, the leading Russian opposition activist Alexey Navalny.

“I used to have a nightmare many times that I wake up from someone calling me and saying, Alexey was killed or something very bad happened to him,” Volkov recalls in an interview with CNN. “I had this nightmare at least 10 times in my life.”

Last week he lived that nightmare. An early morning phone call told him Navalny had collapsed while on a flight from the Siberian city of Tomsk and he was now in a coma. He says having anticipated this moment didn’t make the reality any easier to process.

“I was terrified. Of course, emotionally, it was a very dramatic blow,” he says. “So it took me several hours to concentrate.”

But as Navalny’s chief of staff he had a job to do: get him out of Russia and into trusted medical care.

Volkov, along with the German NGO, Cinema for Peace, organized an air ambulance that was made to wait at a nearby airport while Russian doctors insisted Navalny was too ill to be moved.

Navalny’s allies believe that delay was deliberate and intended to make the poison in his body undetectable.

He was eventually flown to Berlin where doctors at the Charite hospital determined he was likely poisoned by a substance from a group of chemicals known as cholinesterase inhibitors. The medical team’s inability so far to determine the specific poison has been seized on by Russian President Vladimir Putin’s spokesperson as justification for Russian authorities not yet opening a criminal investigation.

Volkov says that response is just one factor that points to the Russian state’s involvement in an attempt to assassinate Navalny.

“Based on the information I have at this point of time, I strongly believe it’s either the state or part of the state. So as of now, we don’t have a proof that Putin ordered it. So it might be some of the government agencies. But the level of organization, the poisons that they used. It’s not something you can buy in a pharmacy, in a drugstore on the next corner,” Volkov says.

Russia denies any attempt to harm Navalny.

German army medics transport a stretcher carrying Alexey Navalny at Berlin's Charite hospital.
Leonid Volkov says his friend Alexey Navalny knew the risks of being such a high-profile opposition figure in Russia.

‘Only protection: Publicity’

Volkov says his friend knew the risks. Other opposition figures have been shot, beaten and poisoned. Navalny, Volkov says, never thought about changing his behavior or quitting his work.

“So when we discussed it, our thought was the only possible protection… is maximum publicity. So the greater the number of our supporters, the greater his approval ratings, the larger the risks the Kremlin would be taking trying to kill him.”

So why now? Navalny has been openly defying Russia’s elite for 10 years. If people within the Russian state tried to kill Navalny, why would they risk turning a much-admired activist into a political martyr?

Volkov says the timing points to two possible factors.

The first: Belarus. Navalny had loudly supported the mass protests in the neighboring country after its disputed presidential election. He called for Russians to show equal passion to overthrow their own leaders. Putin has often expressed his loathing for street-led revolutions.

Alexey Navalny's national organization had launched a campaign promoting tactical voting in Russia.

And in two weeks Russia will hold its own municipal elections. Navalny’s national organization has been preparing for this event with a campaign promoting tactical voting. It proved effective in defeating pro-Putin candidates in last year’s Moscow assembly election.

Ultimately, Volkov says, someone made a calculation: The benefits of removing Navalny from Russian political life would outweigh any problems from his outraged supporters.

“It was an attempt to kill, not to scare him off,” Volkov says.

Navalny’s recovery is expected to be slow. It will be some time before we know if and when he will resume his role as Kremlin’s strongest and most effective critic.

What does Russia without Navalny look like? “We’re not considering that,” Volkov says.

CNN’s Sebastian Shukla and John Torigoe contributed to this report.