LONDON—British political consultants that worked for Donald Trump’s presidential campaign said they secretly used proxy organizations and super PACs to spread ads in the U.S. that could not be traced back to the Trump campaign.

Alexander Nix, the CEO of Cambridge Analytica, was secretly recorded by undercover reporters from Channel 4 in Britain who were posing as prospective clients. “There’s no evidence, there’s no paper trail, there’s nothing,” said Nix, reassuring them that his company’s dirty tricks for his clients would never be detected.

Nix said Cambridge Analytica used encrypted emails that were timed to self-destruct and boasted that U.S. politicians on the congressional committees weren’t smart enough to catch him out. “They’re politicians, they’re not technical. They don’t understand,” he said.

Nix claimed they had overseen much of the Trump presidential campaign, we “ran all the digital campaign, the television campaign and our data informed all the strategy.”

He said he had met Trump “many times.”

One of Cambridge Analytica’s biggest investors and board members, Republican super-donor Rebekah Mercer, told The Daily Beast Monday that she was standing by the company after it was accused of misusing 50 million harvested Facebook profiles . Steve Bannon, Trump’s former chief strategist, was another former investor and board member.

The company’s managing director, Mark Turnbull, told the undercover reporters that they had created something called the “Defeat Crooked Hillary” ad campaign.

Turnbull: “The brand was ‘Defeat Crooked Hillary’. You’ll remember this of course? ‘Crooked Hillary’ - and the zeros, the OO of crooked were a pair of hand-cuffs and it was all about….”

Reporter: “Like prisoner?”

Turnbull: “She belongs behind bars…”

Reporter: “And you have created this?”

Turnbull: “Defeat Crooked Hillary. And then, we made creative, hundreds of different kinds of creative, and we put it online.”

A Facebook page, website, online and TV ads of the same name were created during the campaign. The website said it was a special project of Make America Number 1, a super PAC reportedly funded by the Mercer family, who bankrolls Cambridge Analytica.

A spokesman for Cambridge Analytica said that the company “has been completely transparent about our simultaneous work on both political campaigns and political action committees (including publicly declaring our work on both with FEC filings). We have strict firewall practises to ensure no coordination between regulated groups, including the teams working on non-coordinated campaigns being physically separated, using different servers and being banned from communicating with each other.”

Minutes before Channel 4 broadcast aired in the U.K., Cambridge Analytica suspended Nix as CEO pending an investigation into his work.

Dr. Alex Tayler, the company’s chief data scientist, was recorded explaining how campaigns could secretly direct other organizations to spread their message.

“Sometimes you can use proxy organisations who are already there. You feed them. They are civil society organizations… Charities or activist groups, and we use them—feed them the material and they do the work,” he said. “So this stuff infiltrates the online community and expands but with no branding—so it’s unattributable, untrackable.”

Over the weekend it was claimed that Cambridge Analytica had misused data harvested from 50 million Facebook profiles to calibrate their message and target U.S. voters who might be susceptible.

Christopher Wylie, a Cambridge Analytica whistleblower, said they had been testing slogans such as “drain the swamp” and “build that wall,” as early as 2014. “We were testing these narratives well before Trump even announced,” he told CNN. “We were finding there were pockets of Americans who this really appealed to. Steve Bannon knew that, because we were doing the research on it.”

Nix, who appeared before the House Intelligence Committee in December 2017, told the undercover reporters that there was no need to worry about Congressional oversight. He said the Republican members asked just three questions. “After five minutes—done.”

“They’re politicians, they’re not technical. They don’t understand how it works,” he said, explaining that the Democrats were a little more persistent—questioning him for two hours—because they were motivated by “sour grapes.”

On Monday, the top Democrat on the Senate Intelligence Committee, Mark Warner, called for Nix and his colleagues to return to the Hill for a rematch.