LONDON—Vladimir Putin offered Donald Trump a trade at the Helsinki summit: I’ll let you interview the 12 Russian intelligence agents accused of hacking Democratic emails and interfering in the 2016 U.S. election, if you give my interrogators access to Bill Browder.

Browder, a U.S.-born hedge fund manager, is the leader of a campaign against Putin that stems from the death of his lawyer Sergei Magnitsky, who exposed a $230 million tax fraud in Russia. According to the Kremlin, Browder was the real criminal and Putin has pursued him all over the world.

Seven countries, including the U.S. under President Obama, have sided with Browder and passed anti-corruption legislation targeting Russia in the name of Magnitsky—sending Putin into paroxysms of rage.

The notorious Trump Tower meeting, attended by several Russians and Donald Trump Jr. and Jared Kushner in June 2016, was one of many attempts by Putin’s allies to have the Magnitsky Act overturned.

Having been caught red-handed by the Mueller investigation directly intervening in the U.S. presidential election via his GRU army intelligence agents, Putin saw another opportunity to go after Browder. He apparently believes Trump would be willing to sell out Browder in exchange for pursuing those 12 GRU operatives.

“We can let them into the country, and they will be present at the questioning, but in this case there is another condition,” Putin said, standing alongside Trump to whom he has presumably just offered this exchange behind closed doors. “We would expect that the Americans would reciprocate… We can bring up Mr. Browder.”

Trump did not respond on stage, but Browder is confident that there’s nothing the U.S. president can do to hurt the British citizen even if he was tempted.

“I think that the rule of law in America is stronger than any backroom deal he makes with Putin,” he told The Daily Beast.

He said he could envisage Trump trying to sell out his rights, but believes that the Department of Justice would soon analyze the legality of the request to interview him and they would “come to the conclusion very quickly that it's illegal and also politically disastrous.”

Putin claimed that Browder and his allies had donated $400 million to the Hillary Clinton campaign in an apparent attempt to persuade Trump that he was worthy of sacrifice. Browder says he did not donate “a penny.”

Browder said he was delighted that Putin was still furious with him. “I couldn't be better. I got the president of the Russian Federation on his heels in absolute panic about what I'm doing to disclose his crimes to the world—this was an emotional reaction,” he said. “As a KGB person, he doesn't like people to know his weakness.”