"I am against bloody revolution, I am for peaceful transformation. Putin has 140 billion US dollars ... It's easy to understand he will try to protect this money and his freedom and his power. That's why we must think about a marathon. Not a sprint, but a marathon." - Boris Nemtsov on Day 6, February, 2012

Boris Nemtsov's marathon ended when he was gunned down late last Friday night in Moscow. He was shot four times in the back within sight of the Kremlin. The Russian government has denied any part in the crime. Once set to become Boris Yeltsin's successor, Nemtsov went on to be a vocal opponent of Russian President Vladimir Putin. Garry Kasparov, a close friend and political ally of Boris Nemtsov, says the murder sends a message that "no-one is safe."

Mr. Kasparov rose to fame as a chess Grandmaster and was the human opponent against IBM's chess super-computer Deep Blue in a pair of high-profile matches in the 90's. He was the co-founder of the Democratic Party of Russia, and he now serves as the chair of the New York-based Human Rights Foundation. He spoke to Brent Bambury from New York City on Thursday.

Brent Bambury: My colleague Peter Armstrong spoke to Boris Nemtsov in February, 2012 - in advance of the Russian elections set for March of that year - I want you to listen to the end of that conversation:

Peter Armstrong: So is that the important thing now now, not to defeat him, but to reduce his mandate?

Boris Nemtsov: Yes, to reduce... Absolutely.

PA: And do you think that's a deliverable goal in March?

BN: It depends on our activity. It depends on our will. It depends on our unity.

PA: Do you imagine you'll be spending more time in jail in the near future?

BN: I was in jail. Well, if you're in the opposition to Putin, you have to take into account risks. Jail is risk. But what is my choice: to emigrate or to continue. I prefer to continue.

That was Boris Nemtsov in February, 2012. How does it feel to hear his voice for you today - a week after his murder?

Garry Kasparov: It's still difficult to hear his voice. Boris was a big man, with a big voice and an imposing presence, always full of energy. It's hard to believe he's not around criticizing - no, not criticizing, blasting Putin's regime for violation of human rights, writing his reports revealing endemic corruption and other crimes of the regime. It is tragic, not just for the opposition but for the country itself. The message is very clear: no-one is safe.

He made the choice to stay in Russia, he knew that there were risks ... did you ever tell him that maybe he should get out, that maybe he could be more effective agitating from outside the country?

Look, he said he made his choice. Actually, two weeks before his death he talked about this risk in more explicit terms. He sensed the danger and he was talking about fear for his own life. And I know that his mother warned him many times because Boris was not hiding. He was a frequent guest at my home and he spoke to my mother when I was still in Moscow. And he told us his mother was warning him saying, 'Boris, unless you stop, one day Putin will kill you."

FILE - In this file photo taken on Sunday, May 6, 2012, Opposition leader Boris Nemtsov uses a loud speaker during an opposition rally in downtown Moscow, Russia. (The Associated Press)

So he did think he would be killed? Because some people felt that he was such a high-profile member of the opposition, that protected him...

Boris was such an optimist so I think it was difficult for him to imagine that this would happen. Even recognizing the danger, even seeing the degradation of the Putin regime and recognizing that with so much blood on their hands they can go after anybody... but he made his choice. He was bravest of us all, and he was talking of the crimes of the regime up to the last minute. We know that there was material gathered by Boris for a new report. This time it was about the war in Ukraine and the presence of Russian regulars - regular troops - in eastern Ukraine.

In a Wall Street Journal op-ed this week you wrote, "The question, 'Did Putin give the order?' rings hollow." Can you explain what you mean by that?

It could be Putin. It could be someone from his inner circle. The operation that led to the elimination of Boris took place just outside the Kremlin. This is probably one of the most protected areas in the world, with more cameras videotaping every square inch than there are at Fort Knox, for instance. It could be handled only with the full awareness of the security system that is surrounding the Kremlin. At the end of the day whether it's Putin or someone close to him doesn't matter. What matters is they decided he was too loud and there was too much of Boris. He was very vocal about aggression in Ukraine. Every dictatorship reaches its limits of tolerance with people who are speaking against it, even if they are famous and prominent like Boris Nemtsov.

When you think of Boris Nemtsov, is there a time that you remember that could help us understand what kind of a man he was?

He was dreaming about moving Russia in the right direction without a drop of blood. It's tragic that eventually it was in his own blood to be paid for, for us moving forward. - Garry Kasparov on his friend, the late Boris Nemtsov.

Boris was big. And my memories of him are also sizable. The man had an imposing presence. He could fill a room. We had our a lot of arguments. I had my strong views and Boris could disagree, but that is normal in any democratic organization. But Boris was always sincere in his arguments. I think he was wrong, dreaming about Russia being transformed into a normal democratic state without violence and I told him that. But he loved our country and he thought that the greatest tragedy for Russia would be another revolution, that turmoil. He was dreaming about moving Russia in the right direction without a drop of blood. It's tragic that eventually it was in his own blood to be paid for, for us moving forward.

We're looking at the second decade of Putin's control, would you return to Russia at this point?

I can't return. It would be a one-way ticket. Putin's dictatorship now is at its final stage, its most dangerous one. It is spreading this cancer to Russia's neighbours. Unless it is stopped and cut, it will keep moving forward. Vladimir Putin is willing to test not only former Soviet republics, not only Europe, but the United States and NATO to see whether they are up to the challenge. He will test them by demonstrating his resolve to destroy the system of international security that has been built since 1945. I think this should be taken seriously because, like in the 1930s, we'd rather react earlier than later.

This must be very difficult for you because this is your homeland and there was a time not so long ago in 2008, when you hoped to run for President of Russia and now you're telling me that you can't even ever return to the country. Does this mean that Vladimir Putin has won?

Look, when you mention running for President, you should not mislead your listeners because everything connected to these so-called elections in Russia was more of a demonstration. You can not take part in the elections unless you are approved by the Kremlin and all I did in 2008 was to demonstrate that it couldn't happen unless the Kremlin wants you to be a puppet in the process.

OK - but you were an active player at a pivotal moment in Russia's history.

Absolutely. We were in the streets. That's what we did with Boris. We tried to revitalize the democratic spirit in Russia and to make sure that people will regain their voice.

Is that dream dead now? Is there still a chance?

Of course there's a chance because all dictators meet the same end. Putin is dominant now, as Hitler was in 1938 or 1939 but the problem is all these dictatorships run out of steam. Putin's Russia is in terrible economic shape and the foreign aggression remains the only element of Putin's mythological charisma. So the moment Russia's aggressive foreign policy comes to an end and the free world builds a strong defensive perimeter, Putin's aura of invincibility will be destroyed and he'll be gone.

This week, you addressed a U.S. Senate subcommittee. What was the most important point you wanted to impress on them?

These hearings were about Ukraine and the very dangerous situation there, the continuous Russian aggression that is threatening not just further occupation of Ukrainian territory but also the existence of Ukrainian statehood, which I believe is Putin's ultimate goal.

You told the Senate that Putin and his elite believe there is nothing they can't do, that they can get away with anything. Are they right?

It depends how you look at this. They might be right today but historically they will pay the same price as the Nazi elite.

Is there anything you learned from your years as a chess champion that you apply to the fight for democracy in Russia?

You have to be determined to reach your goal. If you try to find any strategy that involves your opponents who are paying no attention to the rules and can change them at any time they want, you will be on the losing side. So it's all about psychology rather than following the strategic line.

Garry Kasparov, thank you for spending time with us.

Thank you.