AMNA NAWAZ: It's the highest profile killing of a supporter of Russia's war in Ukraine.

This weekend, a pro-war blogger died in an explosion at a cafe in St. Petersburg.

Russian authorities blamed Ukraine and have arrested an anti-war activist.

But, as Nick Schifrin reports, the cafe's owner, a well-known Putin ally, says the plot is thicker.

NICK SCHIFRIN: In front of his own photo, Vladlen Tatarsky accepted his Trojan horse, a bust of himself.

Moments after this was filmed, the bust exploded and destroyed the cafe, leaving his dead body and a mangled mess.

Tatarsky was a well-known blogger and advocate for Russia's war in Ukraine.

He was actually Ukrainian-born, a furniture-maker, turned convicted bank robber, turned ultranationalist influencer, who's shown off the Kremlin to his 560,000 followers.

VLADLEN TATARSKY, Blogger (through translator): We will defeat everyone.

We will kill everyone.

We will rob everyone we need.

Everything will be as we like.

NICK SCHIFRIN: Russia blamed this woman, anti-war activist Daria Trepova, who brought the bust to the cafe in video posted by a Russian news outlet.

Russian authorities accused her of acting on behalf of Ukrainian intelligence.

But the cafe's owner begs to differ.

Yevgeny Prigozhin was once known as Putin's chef, who owned a catering service that catered to the Kremlin.

But he's emerged from the shadows to help fund and fuel the war, as the chief financier of the Wagner paramilitary group.

He personally recruited tens of thousands of soldiers, many from Russian prisons, and sent them into hell.

Bakhmut once had a population of 75,000.

Today, Russia has destroyed it and calls it victory.

Wagner has lead the fighting and dying.

Prigozhin posted this photo.

The U.S. says more than 30-thousand Wagner soldiers have been wounded or killed.

Last night, Prigozhin claimed Wagner had seized Bakhmut's center.

The flag, says to the memory of Vladlen Tatarsky.

Prigozhin, like Tatarsky, is a pardoned former convict who became a prominent ultranationalist.

And Prigozhin had given his cafe to Tatarsky's group.

But, today, Prigozhin posted an audio message, saying the explosion wasn't caused by Ukraine's government.

YEVGENY PRIGOZHIN, Wagner Group (through translator): I would not blame the Kyiv regime for these actions.

I think there is a group of radicals who hardly have any connections to the government.

NICK SCHIFRIN: Some Russian government officials claimed the woman arrested in Tatarsky's death worked with Russian opposition leader Alexey Navalny's organization.

He is currently in Russian prison.

And neither Navalny nor his group have ever had any connection to violence in Russia.

To explore the implications of this bombing, we turn to Candace Rondeaux, a senior director at New America, a Washington, D.C.- based think tank.

She's written extensively about the Wagner Group, and its leader, Yevgeny Prigozhin.

Candace Rondeaux, welcome to the "NewsHour."

Think you very much.

Tell us more about who was Tatarsky was why his death is so significant.

CANDACE RONDEAUX, Senior Director, New America: Vladlen Tatarsky was probably one of the most prolific military bloggers, pro-Russian military bloggers, on the social media channels that are popular with Russian speakers.

He had a huge following.

It was sometime around 2017-2018 that he became very popular for starting a social media vertical called Reverse Side of the Medal, which is basically a mouthpiece and kind of a soapbox for some of the most extreme ultranationalist elements of Russia's right-wing.

And, in particular, Reverse Side of the Medal is a kind of cultural hub for the Wagner Group and Russian mercenaries and soldiers of fortune.

NICK SCHIFRIN: And so fast-forward to the full-scale invasion.

He is one of the most prominent bloggers not only advocating for the war, but, in fact, pushing the military and the government for more war.

CANDACE RONDEAUX: The one thing to understand about Tatarsky and Reverse Side of the Medal is that job number one was to stoke passion for war.

Job number two was to make sure that that passion could be converted into the mobilization of forces on the sly, on the stealth.

And he succeeded in doing that by kind of selling the Wagner Group brand, stealthy, shadowy, high-risk covert operators, masked men doing daring things in Donbass.

And he did that very well by actually cultivating relationships with real-world Wagner Group fighters and bringing them onto his YouTube channel, doing short videos and Telegram.

And he basically grew the brand through that social media channel.

But, also, in St. Petersburg, he was kind of becoming like a cafe influencer.

That's why the Street Food No.

1 restaurant was hit.

Essentially, Yevgeny Prigozhin had given it to Tatarsky as kind of like a headquarters for this cultural move of ultranationalist, pro-war sentiment to be mobilized not just on media channels, but also in real life.

NICK SCHIFRIN: And this was an only as you have pointed out, Prigozhin's cafe.

This was a neighborhood seen as Prigozhin's turf.

How much of this is about sending a message, as far as we can tell, to Prigozhin's himself.

CANDACE RONDEAUX: That restaurant is just five blocks, not even three blocks from Yevgeny Prigozhin's very first high-style restaurant.

It's called the Old Customs House.

I mean, it was a big mafia hangout, a big -- a big hangout for Vladimir Putin back in the day, when he was deputy mayor in St. Petersburg.

That whole block, that whole little area where this bombing occurred, has been basically Yevgeny Prigozhin's playground and turf and headquarters for the better part of 30 years now.

And so striking there really sends a message not just to Prigozhin, but to all the people who are sort of involved in his business enterprises, that they better stay on watch.

NICK SCHIFRIN: You point out how long Prigozhin goes back with Putin.

But, more recently, he's been fighting with some of the senior Russian defense officials, Sergei Shoigu, the defense minister, the equivalent of their chief of staff, Valery Gerasimov, has -- he's accused both of them actually killing Wagner soldiers in Ukraine.

And there's yet again today another gap between what Prigozhin is saying and the Kremlin talking points.

What's behind that divide?

CANDACE RONDEAUX: You know, it's very hard with Yevgeny Prigozhin to discern how much is theater and then how much is real.

But it has been clear over the last, I'd say, nine months or so, since the battle of Bakhmut began in Ukraine, that he finds himself at the front lines of basically a meat grinder.

And there's been a lot of complaints about sort of shell hunger, that is to say, not enough ammunition, not enough shells to go around for the artillery that's required to beat back the Ukrainian counteroffensive in Bakhmut.

And he's become increasingly louder and louder.

And he's had the backing of hundreds of thousands of followers on channels like the one that Vladlen Tatarsky used to run.

And so that's kind of given him a sort of sense of confidence.

He's biting the hand that feeds him, basically.

At the same time, he also seems to have a political strategy, one in which he understands that, the minute the battle of Bakhmut falls one way or the other, his utility, politically and militarily, is vastly diminished.

And so, in a way, the peacocking that you see online, the constant sort of stream of invective towards Shoigu, as well as Gerasimov, all of that is also a part of a larger design to insulate himself from the potential that he becomes expendable.

But I think this message today with the bombing of Tatarsky is to say, indeed, you are expendable, Mr. Prigozhin, and you better be on watch.

NICK SCHIFRIN: Candace Rondeaux, thank you very much.

CANDACE RONDEAUX: Thank you.