HARI SREENIVASAN: We dig deeper into the story with Michael McFaul, U.S. ambassador to Russia from 2012 to 2014. He's now a professor at Stanford University. And Steven Lee Myers, he covers foreign affairs and national security at The New York Times. He was based in Russia from 2002 to 2007. He's also the author of "The New Tsar: The Rise and Reign of Vladimir Putin."

Steven Lee Myers, I want to ask you first, who was this individual that was killed?

STEVEN LEE MYERS, New York Times: Alexander Litvinenko was a fairly obscure intelligence officer in the KGB and then later the FSB in the '90s, wasn't very well-known until he very sensationally came forward with accusations that the unit that he worked for was involved in corrupt activities and in fact an assassination plot.

When he came forward at the time — this was in 1998 — the director of the FSB at the time, the federal security service, was Vladimir Putin.

HARI SREENIVASAN: So, Steven, staying with you for a second, in your reporting at the time, a lot of people suspected this. What did we learn today from this report?

STEVEN LEE MYERS: You know, people who followed this inquiry, which really was an extraordinary process, might not be that surprised by the conclusions that were in it.

But I think the tone of it and the accusation linking it, though, with a caveat, to the Kremlin and Putin himself is really what was so striking, to see all these facts laid out. A lot of what was known about this case dates back to the investigation that happened in 2006 and 2007.

And when the British originally charged the two suspects, you know, many of the details were you know, many of the details were already known at that time, but I think that there was an eagerness inside the U.K. especially to learn more about this case and who did order it, and, you know, the judge's report today took that to the top of the Kremlin.

HARI SREENIVASAN: Michael McFaul, does this change your understanding of the events?

MICHAEL MCFAUL, Former U.S. Ambassador to Russia: No.

I, too, like Steven, have followed this case for a long time both as an academic and then in the government. I have only had a chance to skim the entire report. I haven't read everything, but I have read the conclusions closely, and I want to applaud them for doing this. I think it's very important, even if nothing more comes of it, that somebody went to the trouble to document all this for history and so that this has been recorded.

Having looked at it, there is no new smoking gun. There is no secret tape that recorded Putin giving the order or Mr. Patrushev giving the order, but it just puts together the circumstantial evidence, which is to say that these two agents came from Moscow.

They had polonium, something you can't just buy on the streets. They poisoned him. They went back to Moscow and they have been protected by the Russian state ever since. In fact, Mr. Putin has given Mr. Lugovoi a state award.

And it's based on that, that they come to their conclusions, and it's pretty damning conclusions, therefore, for both President Putin and at the time the head of the FSB, Mr. Nikolai Patrushev.

HARI SREENIVASAN: Steven Lee Myers, does this almost bolster Putin's image as a tough guy, as someone that get things done, even having this out there?

STEVEN LEE MYERS: I don't think anybody inside the Kremlin welcomes this kind of attention or the accusations which again have been out there the last 10 years.

They have vigorously fought them. Putin doesn't want to be portrayed as somebody who would carry out this kind of attack, ordering this kind of assassination. That said, Litvinenko was widely reviled in the Russian elite, especially among the security services.

And even in the testimony that is included in the report today, one of the suspects said that the killing was meant to send a message to others who might betray their oath to the state in Russia.

HARI SREENIVASAN: Michael McFaul, I see you agreeing there. This was a killing that was meant to send a message by that slow, painful death?

MICHAEL MCFAUL: Oh, absolutely. I mean, he was a traitor. Remember, he worked for the KGB, then the FSB, the same organizations that Mr. Putin and Patrushev worked for.

He then defected. He then made these claims — that's in the report again — that the FSB orchestrated terrorist attacks against Russian citizens back in the fall of 1989 as a way to rally Russians around the flag and support ultimately President Putin. That was the first time that he ran for president.

So there's no doubt that they hated him. They made that very clear. And they were sending a signal. And I want to point out, there's been a lot of assassinations, there's been a lot of killings. Just last year, the leading figure of the opposition, Boris Nemtsov, was murdered, assassinated just a few feet from the Kremlin walls, again, with all this ambiguous notion, actually who ordered it, who didn't.

But it's a pattern. It's not just a one-off. And the last thing I want to remind you of, even if they didn't make these calls, right, even if somehow this was a rogue operation, that's also pretty damning. That means that President Putin is not in charge of his state and that people within the regime can carry out assassinations without his blessing. That's also not a very good message about his control within Russia.

HARI SREENIVASAN: Steven, what's the response been from Russia today?

STEVEN LEE MYERS: You know, as you would expect, and as it has been from the very beginning, they have denounced this investigation. They say that the accusations that the Russian state was involved at all is part of a politically motivated smear campaign against Russia and against Putin himself.

So, you know, it's hard for them, I think, in Russia to understand this or accept this as an independent inquiry. They say the whole thing was politicized to come to a predetermined conclusion.

HARI SREENIVASAN: Finally, Michael McFaul, what about the diplomatic consequences of this? The U.K. and the U.S. are kind of in a delicate dance with Russia right now, especially when it comes to Syria.

MICHAEL MCFAUL: Well, I think for Prime Minister Cameron, it's going to be very difficult, because they took years to get over this big interruption in their bilateral relationship. And they were just slowly creeping towards a better relationship when I was ambassador, and then the invasion of Ukraine set that back.

We're now in this moment, as you just noted, of trying to cooperate with Russia on Syria, both on a political solution, but also on the fight against ISIS. And, therefore, I think they're going to try to do damage control. That would be my prediction.

HARI SREENIVASAN: All right, Michael McFaul, Steven Lee Myers, thanks so much.

STEVEN LEE MYERS: Thank you.

MICHAEL MCFAUL: Thank you.