Natalia Pelevina, a Russian political activist at the heart of a shocking sex scandal, has no doubts about who is responsible for revealing her affair with a former Russian prime minister.

A secret video of her and Mikhail Kasyanov showing intimate bedroom sex scenes and frank private conversations was baldly exposed last Friday on national television.

Pelevina is convinced the Russian security services planted the recording devices to entrap the couple at the behest of the president.

"It had to be Putin. I have no doubt about that," Pelevina told CBC during an exclusive interview in Moscow this week.

She hadn't spoken publicly about the sex scandal since it broke last week. Kasyanov is chairman of PARNAS, a liberal opposition party in Russia. Pelevina is his political assistant and was, until this week, a member of the party executive.

Russian broadcaster NTV aired a 40-minute special program liberally laced with scenes from the secretly taped video of the two.

Natalia Pelevina believes Russian President Vladimir Putin is ultimately responsible for the release of a video showing her and her lover, Mikhail Kasyanov, having sex. The tape was played on national Russian television last week. (Corinne Seminoff/CBC)

Since being turfed from Vladimir Putin's government in 2004, Kasyanov has been a prominent Kremlin critic.

The black and white video played on NTV, with clear audio, first showed Pelevina in sexy lingerie, then the two lovers naked in various stages of cooing and lovemaking. It seemed to have been quickly edited to highlight salacious, sometimes cringing moments of intimate talk between the two.

"What has come out, the just unthinkable awfulness of it, really tells me that he (Putin) did not only go after Kasyanov this time. The goal was to destroy him," Pelevina told CBC News.

There were warning signs

Pelevina believes a surveillance camera was installed behind a bedroom wall and a microphone hidden under the kitchen table in a private Moscow apartment owned by Kasyanov.

Pelevina and Kasyanov often met there during their long affair. She is 38 and single; he is 58, married with two children. They worked together in the trenches of Russia's battered opposition. Both were deep in preparations for this fall's parliamentary elections when the video emerged.

Pelevina believes the secret surveillance of a private apartment owned by Kasyanov, a married father of two, was carried out by Russia's security services and lasted six months. (NTV)

Pelevina, born in Moscow, lived in Britain until four years ago. She's been an activist with the Magnitksy Justice Campaign, formed in support of Sergei Magnitsky, a Russian lawyer who died in prison after blowing the whistle on corruption in Russian state-owned enterprises. She returned to Moscow, she says, to actively work with Russia's opposition.

She acknowledges she and Kasyanov were careless in their relationship, especially given that they had received warning signs that they were being watched. At a restaurant recently, the owner left them a note in their menu saying, "Don't go in there," indicating a corner room. "It was bugged just before you arrived."

They had discussed how they might be tailed and watched.

"We never thought they would go this far," Pelevina said.

6 months of surveillance

NTV did not explain how it got the secret video, but the channel is close to the Kremlin. The footage that aired appeared to show one night of sex, but Pelevina says the scenes were edited together from, she believes, six months of secret surveillance. She is horrified thinking the couple may have been spied on for that long.

There were obvious signs that pressure was building on Kasyanov — beginning in January, when Chechen leader Ramzan Kadyrov posted video of Kasyanov inside a sniper's crosshairs. A few weeks later, he was "pied" in the face at a restaurant, a favourite threatening tactic of provocateurs.

Kasyanov is chairman of PARNAS, a liberal opposition party in Russia, and was prime minister before he fell out of favour and was ousted by Putin in 2004. Pelevina is his political assistant and was a member of the party executive until she resigned this week. (Corinne Seminoff/CBC)

In an interview with CBC in February, Kasyanov said "the situation is worsening every day. Putin's pursuing a tough policy, squeezing the whole political environment in Russia. We have permanent blackmailing of the opposition. We face problems every day."

Kasyanov's adultery wasn't the only "revelation" in the video. Clear audio recordings reveal Pelevina, a would-be parliamentary candidate, aggressively badmouthing other leaders of the opposition. She is heard saying that an alliance with opposition leader Alexei Navalny was necessary, but she clearly detests him.

"Navalny is a piece of shit," she's heard to say.

She goes on to call the deputy chairman of PARNAS, Ilya Yashin, "a freak who's willing to sell his place in the campaign for $30,000."

In an exclusive interview with CBC News, Pelevina told Susan Ormiston she's convinced Putin's aim was to 'destroy' Kasyanov, who is running in the fall parliamentary elections and has been the target of past intimidation tactics along with other members of the opposition. (Corinne Seminoff/CBC)

Kasyanov is heard trying to subdue her strong opinions, then telling her he'll put her in the Duma (Russia's parliament) and build the party around her.

The political talk is edited over scenes in the bedroom appearing as if it was pillow talk, but Pelevina says much of it was said over wine and cheese in the kitchen, where they often unloaded daily frustrations and talked politics.

'The words I used were foul, but I'm human'

Pelevina has resigned her seat on PARNAS's political council in the wake of the scandal.

"I'm not making excuses but … they cut all the terrible things in such a way that it looks like one crazy verbal explosion, and it was never like that," she said. "The words I used were foul, but I'm human, and when you get upset, you sometimes say things you regret."

But there is no doubt the video hurts the opposition, already weak and struggling to unite in order to present a stronger alternative to an overwhelmingly popular governing party. With only five months to go before the election for the Duma, the opposition is reeling.

Dimitry Nekrasov, a moderate opposition politician, says the greater crime in the sex tape scandal is not adultery but using state power to suppress opposition. (Jean Francois Bisson/CBC)

"I don't want them (security services) to succeed in this. It's not right," said Pelevina. "All of us have sacrificed a lot. It's a tough life in Russia right now, and to be in opposition, it's like being at war."

The most damaging information was not the fact of sexual affairs of Mr. Kasyanov , but the fact of using state power, state secret services, against the opposition. - Dmitry Nekrasov , opposition politician

Media reported that millions of Russians watched the NTV broadcast, which raised the bar on political sabotage to new levels, even in a country used to political smut.

"It's damaging, of course," says Dmitry Nekrasov, running for a seat in the Duma this fall.

"But it won't be as damaging for Kasyanov as if it happened in many Western countries. It won't be so harmful.

"In Russia, there's a lot of damaging information regarding all politicians, and it's used from time to time by different parties. That's why people don't believe in many things."

Use of state power against the opposition

Nekrasov concurs that Kasyanov should have been far more careful in the current climate of surveillance.

But "in my opinion, the most damaging information was not the fact of sexual affairs of Mr. Kasyanov, but the fact of using state power, state secret services, against the opposition," Nekrasov siad.

The fact that Mikhail was and is married, yes, it is wrong, but unfortunately, what we felt was stronger than that fact. - Natalia Pelevina

"Nothing we did was illegal," said Pelevina angrily. She paused, trying to collect herself. Speaking about the affair is clearly painful for her.

"The fact that Mikhail was and is married, yes, it is wrong, but unfortunately, what we felt was stronger than that fact. We weren't able to end the relationship."

The secret surveillance wasn't the first attack aimed at Pelevina. Only three weeks ago, she was charged with possessing a pen-size spy camera, the kind you can buy at a gadget shop. She says it was a gag gift from her sister. She now faces a criminal charge, and even though she has British residency, she cannot leave Moscow. If convicted, she can never run for political office.

Kasyanov and fellow opposition leader Boris Nemtsov, who was murdered on a Moscow bridge in February 2015.

As for Kasyanov, the married man, father and seasoned warrior of Russian politics, he has yet to surface to explain his behaviour. It's not at all clear whether, in political affairs, this is his fatal blow.

But in the affairs of the heart? The tryst, exposed for all of Russia to see, has left many people deeply hurt and damaged.

Pelevina is humiliated. The affair, she says, is over.

"I wish he (Kasyanov) had had better judgment. I wish he had known that this would be possible," she said.

Pelevina said she spoke to Kasyanov several days after the scandal broke. He was very emotional.

"[He said], 'I did this to you. I did it.' And he did. I trusted him to know these things," said Pelevina, tears welling up.

"But I can't be angry at him, because I loved that man very much."

Russian politics is cutthroat. This isn't the first dirty sex tape scandal, nor will it be the last. There is a degree of indifference to yet more political dirty tricks; they're predictable.