LONDON—When Nigel Farage, Mr. Brexit, watched Donald Trump accept the Republican Party’s presidential nomination at the convention last year he had an extremely unlikely companion. His closest aide on the trip was an offshore investment expert who had boasted on the dark web about his ability to launder money illegally in and out of the United States.

The aide, George Cottrell, was busted at Chicago’s O’Hare airport on his way home to London on July 22, 2016. He would later plead guilty to participating in a scheme “to advertise money laundering services on a TOR network black-market website.”

With questions being raised about a dark money influence on Brexit—and the election of Donald Trump—all of this begs the question: who was this criminal operative chosen to accompany Farage at the RNC where he met with some of Trump’s best known boosters, including Newt Gingrich and Roger Stone?

It was reported earlier this year that Farage is a person of interest in the FBI’s Russia-Trump probe. He appeared alongside Trump at a rally in Mississippi in August 2016, and was one of the first foreign politicians to visit Trump Tower after the shock election victory.

As well as Cottrell’s advertised ability to transmit money across borders without detection, he was well versed in the world of offshore and cross-border banking. Despite having no political experience, this was the man—aged just 22 at the time—Farage chose to run his office at the height of the battle for Brexit. He was also the co-director of Brexit fundraising for UKIP.

Cottrell is young to have developed such knowledge of international finance, but then again he was first registered as the director of a business, Upsilon Investments six years ago while he was still a high school-aged kid —alongside an offshore director based in the British Virgin Islands—according to records lodged with Companies House in London.

Before entering his guilty plea, Cottrell changed his name to George Cotrel. He told the U.S. authorities this was intended to “ distance his previous involvement in certain political activities.” It didn’t work.

Some of those who saw him running around for Farage while working at the pro-Brexit party thought of Cottrell as a “swashbuckler”—a player who remained popular in Farage’s clique not least because he was known to be extremely generous at the bar.

Others say he was a serious operator. “He was a very smart cookie, very clever chap. When I was campaigning with him, he was erudite and had all the attributes going for him,” said Nigel Sussman, the commercial director of the pro-Moscow group Westminster Russia Forum and a former UKIP candidate.

“ He was very well connected,” Sussman told The Daily Beast.

Cottrell had worked for a number of banks, including a most recent role helping high net worth individuals shift their money across borders. He also claims he had been working as a consultant in the financial intelligence unit of an intelligence agency for over a year when he joined UKIP—in a senior role that he undertook for free. “I don't think he was ever paid a bean by the party, not a single bean,” said a party official.

A UKIP insider said he was remarkably effective and knowledgeable for his age. “He’s entirely personable, entirely likeable, a great fun figure and very impressive getting things done,” he said. “He brought us skills of immense chutzpah and phenomenal self-confidence.”

Known as “Posh George” by Farage and his entourage, Cottrell is the nephew of Lord Hesketh, a former Conservative party treasurer who later defected to the more radical right-wing UKIP. His mother, Fiona Cottrell, was reportedly a former girlfriend of Prince Charles.

After Cottrell was released from federal prison in the U.S., former UKIP candidate and party supporter William Cash wrote a sympathetic profile for The Daily Telegraph . As part of a detailed interview, it offered an account of how Cottrell got mixed up in dark web fraud that was radically different from the sworn testimony he gave in court. The article claimed he was approached at his bank by two American businessmen who wanted to sell their property portfolio. His guilty plea, by contrast, admitted that he had offered illicit money laundering services on a TOR site.

While the interview seemed keen to paint a more understanding picture of Cottrell—a young man who got into trouble after struggling with gambling—it does also fill in some of the questions around why Cottrell would prove useful to Farage. It was apparently not just his family connections that secured his job; he was said to have “learned about the murky and complicated world of `shadow banking,', secret offshore accounts and sophisticated financial structures” while he worked at a private bank.

“It was these skills that landed Cottrell an unpaid role” at UKIP according to Cash, who explained that Cottrell went on to work “for an offshore private bank (which was under investigation by the U.S. authorities as a `foreign financial institution of primary money-laundering concern').”

A LinkedIn page in Cottrell’s name is careful not to name all of the banks he has worked for. Instead it talks about working for a private bank as a “Client Manager within cross-border private banking division, responsible for onboarding HNWI individuals,” or as an “advisor to the Investment Manager of a Cayman administered fund of funds.”

The LinkedIn account is less secretive about his “interests.” The 41 organizations listed on the profile include Cottrell’s old school and some of the global financial powerhouses you would expect to see on the account of any financier, but there are also some more unusual connections.

Cottrell is listed as one of just 71 followers of Moldinconbank, a controversial Moldovan bank that was alleged to be at the very center of the “Russian Laundromat” scam that laundered billions in illicit funds from Moscow through fraud, rigged state contracts and tax evasion. Some of those laundered state funds reportedly went to pay foreigners who were acting on behalf of the Kremlin, such as the leader of a small Polish political party who was later arrested on charges of spying for Russia.

The Daily Beast asked the bank whether Cottrell had ever worked with them, but the HR department would only say: “ According to the legislation in force, personal data is granted only with the agreement of the employee.”

Another of the Cottrell account’s “interests” is the bank FBME, an entity which was officially based in Tanzania but had foreign offices in two countries: Cyprus and Russia. According to a U.S. investigation the bank was linked to Bashar al Assad and al Qaeda as well as a $230m fraud against the Russian people uncovered by Sergei Magnitsky, which led to a series of anti-corruption laws being introduced around the world in his name. In 2014, the bank was banned from accessing the American market by the U.S. Treasury after money laundering allegations.

The bank was favored by cronies of Vladimir Putin, some of who used accounts to launder Russian money, as well as the oligarch Mikhail Prokhorov, the owner of the Brooklyn Nets NBA team.

The Cottrell account also listed the Russian banks VTB and Alfa Bank, which the FBI is investigating for links to the Trump organization, as well as Banca Privada d’Andorra (BPA)—which was described as a “primary money laundering concern” linked to Russian crime networks by the U.S. Treasury. BPA did not respond to queries about working with Cottrell.

The Daily Beast cannot independently verify that this LinkedIn page was written by Cottrell but a UKIP spokesman confirmed that the entry about his role in the party was accurate. The LinkedIn account is also linked—from and to—a Twitter account in Cottrell’s name, which has 140 followers. Those followers include a host of UKIP or Brexit campaign insiders including Joe Jenkins, Jack Montgomery, Michael Heaver, Jack Duffin, Andy Wigmore and Nigel Farage as well as Farage’s head of press Dan Jukes and UKIP comms chief Gawain Towler. Towler tagged the account after a night out with Cottrell and his old UKIP buddies “making up” in East London after his deportation from the U.S. earlier this year. A UKIP spokesman said he believed that the account was genuine.

Another follower of the @GeorgeSCottrell account is Ben Harris-Quinney, chairman of the Bow Group—Britain’s oldest conservative think tank.

He told The Daily Beast he had only met Cottrell a handful of times but he described a man who made a big impression in a world where most senior party apparatchiks are a fairly uninspiring. “He’s quite a larger than life, engaging character. I got the impression that he was a bit of a swashbuckler—keen on adventure,” he said.

Harris-Quinney caught up with him in the pub after his release. “People were very surprised when he was arrested because it was so bizarre,” he said. “But he seemed in good spirits and appeared to have taken the whole thing in his stride.”

Indeed, as Cottrell told The Telegraph : “Despite my unfortunate adventure, and everything I went through, I still maintain 2016 was the best year of my life… Brexit and Trump. Nothing better.”

Also on his small list of followers is the journalist Isabel Oakeshott who was with Cottrell and Farage when the young aide was arrested by U.S. agents in Chicago.

At the time, she was writing the book Bad Boys of Brexit, nominally authored by Arron Banks, which names Cottrell as one of just four UKIP staffers in the book’s “cast of characters.”

Banks was by far the biggest financial backer of Brexit—first donating to UKIP and then donating and lending millions to Leave.EU, and another Brexit campaign group. Last month, it was announced that Britain’s Electoral Commission was launching an investigation into whether or not Banks was the “true source” of that money.

Two weeks earlier Open Democracy UK published an investigation into Banks’ finances—raising questions over his wealth and claiming he had been in some financial difficulty before finding almost £10 million to put towards securing Britain’s exit from the European Union. “The self-styled ‘bad boy’ who bankrolled the Leave campaign appears to have exaggerated his wealth. So how did he pay for his Brexit spree?” the report asked.

Banks—who was a member of Farage’s small Brexit inner circle, along with Cottrell—is a colorful character who seems to enjoy fanning the rumors that surround him including suggestions that he has been working on behalf of the Russians.

The week before Christmas this year, Banks and Andy Wigmore, a colleague from Leave.EU, sent a journalist a bottle of Stolichnaya vodka with the message “From Russia With Love.”

In his account of the battle to secure Brexit, he delights in bringing up the spy scandal his Russian wife was caught up in in 2010. Ekaterina Paderina, the daughter of a senior Russian official, who speaks six languages, used an email address with 007 in it and drives the Banks’ family Range Rover with the number plate X MI5 SPY. Banks, who runs a private intelligence company, even details in his book a six-hour lunch at the Russian embassy with Farage, his wife and the Russian ambassador.

In his book, he describes Cottrell as “posh to the point of caricature and willfully abrasive,” as well as detailing the fact that it was Cottrell who accompanied Farage as he made his way from meeting to meeting at the RNC.

Banks also describes the moment Cottrell was apprehended at the airport in Chicago in July 2016:

“Five FBI officers cuffed him. They swooped the minute he set foot on the gangway… It was swift and discreet, and he was hauled off without explanation. Nigel was stunned… [Cottrell] was wealthy enough to give his time for nothing, and had proven hard-working and loyal. There was nothing to suggest any criminal connection.”

Two days later, Farage and Banks found out why Cottrell had been led away: “Nasty shock today as Nigel got Posh George’s full rap sheet. It’s not pretty.”

What looked like a maximum of 20 years in jail was ultimately reduced to eight months when Cottrell agreed to plead guilty on December 19, 2016 .

After his release there were reports that the former UKIP staffer had been given a short sentence because he passed evidence to the U.S. authorities. It is true that court documents filed by the prosecutors asked the judge to offer a reduced sentence because he cooperated and was willing to “provide federal agents additional information after his arrest.”

Officials in the U.S., however, downplayed suggestions that Cottrell had flipped and given key information that might implicate any of his political colleagues as the FBI hunts for a dark money trail connecting Russia, Brexit and the Trump campaign. They said Cottrell would not have been given the lighter sentence and allowed to leave the U.S. if prosecutors were relying on him to give evidence in court.

In the Telegraph interview by a friendly UKIP activist, Cottrell claims that he was lured into the trap while offering to help a customer of his bank. That is entirely inconsistent with the guilty plea he entered in a federal courtroom in Arizona.

His signed declaration said he was snared by undercover IRS-CI agents after proactively offering to help criminals move large sums of money around the world without detection.

“I worked with another individual known as ‘Banker’ to advertise money laundering services on a TOR network black-market website,” he wrote. “I explained various ways criminal proceeds could be laundered—for example, methods to transfer large amounts of cash out of the United States without triggering reporting requirements.”

After his dark web ad attracted the attention of the authorities in March 2014—before he worked for UKIP—Cottrell corresponded with undercover operatives who were posing as drug dealers via the encrypted messaging service Cryptocat before agreeing to travel to Las Vegas to tie up the phony deal.

The federal court heard that Cottrell was extremely well-versed in the intricacies of moving money around. “Cotrel [sic] was surprisingly young—approximately twenty years old at the time—but the IRS-CI agents were impressed with his knowledge of finance, U.S. government procedures, and anti-money laundering laws.”

The question remains, how much of that knowledge was he employing as UKIP’s chief Brexit fundraiser?