The shady, liberal opposition research firm behind the discredited anti-Trump dossier uses smear tactics and intimidation to discredit people who go against its clients, a London-based Venezuelan journalist told Fox News Thursday.

Alek Boyd said Fusion GPS labeled him a “pedophile,” “extortionist” and “drug trafficker” after he criticized Derwick Associates, one of its clients.

“I believe that Fusion GPS’s business is to do basically whatever the paymasters tell them to do,” Boyd said in his first American TV interview. “They are particularly good at spreading misinformation, disinformation and smears.”

The journalist’s testimony comes as a federal judge denied the firm’s request to quash a congressional subpoena for their bank records.

Boyd said Fusion, which describes itself as a “strategic intelligence” outfit, targeted him after he reported on Derwick Associates, a crooked power company with close ties to the Venezuelan government. Derwick Associates allegedly sold faulty electric plants in Venezuela, and skimmed nearly a billion dollars from corrupt contracts with the late Venezuelan dictator Hugo Chavez.

“It is my understanding that [Fusion GPS] were hired basically to smear Derwick opponents and to dispel any possible doubts that regular media may have had at the time,” he told Fox News.

Human rights activist Thor Halvorssen told a similar story last July, when he submitted statements to the Judiciary Committee describing for the record how the firm went after him for whistle-blowing against Derwick.

“Imagine waking up one day and seeing a headline in a fringe website that says that I’m a neocon scam artist and then you read the actual article and it says that I — there in some Facebook posts and Twitter posts that they put out — it says falsely says that I sleep with children, it says that I’m a heroin addict, it says that I’ve been to rehab, it says that I’m an embezzler,” Halvorssen told Fox news’ Tucker Carlson last summer.

He said that it’s a “company that sells itself to the highest bidder to bring together smear campaigns and to try and destroy honest, good people who are going against their clients.”

Boyd told Fox News on Thursday that in the course of his work as an investigative journalist, he had exposed “rampant corruption” related to Derwick, and that Fusion GPS was “retained to basically block and obstruct any further criticism [from] the media.”

According to Boyd, his flat in London was broken into and his laptops stolen. “Pictures of my children were left along with threatening messages of sexual abuse,” Boyd said, adding that he believed that Fusion GPS “had a hand in doing all that.” British police records confirm that Boyd reported a break-in with two laptops stolen from his London apartment in November 2014.

Boyd told Fox News that “a lot of information and a lot of evidence about corruption and scandals in Venezuela that I’ve been compiling throughout the years” were on his computers.

He said that his sources were attacked after the break-in: “People that were believed to be collaborating and sending me information from Venezuela were assaulted in Venezuela by the intelligence police of Mr. Chavez,” he said. “I believe that they were involved in the defamation campaign — smearing campaign — shortly after my apartment was broken into,” he added.

Boyd said Fusion smeared him on the web, labeling him “a pedophile, drug addict and thief.”

“They published this information through a number of social media and websites anonymously. They created fake Twitter accounts with my name, impersonating myself. … They started publishing photos of me walking around London with my daughters. They produced a huge amount of information — fake information — about me, accusing me from being a pedophile to being an extortionist to a drug trafficker to a car thief.”

Three burglary suspects were seen in security camera video released by British police. Boyd said they left pictures of his children inside his coat pocket as a warning. “The message, I believe at the time — we know where you are and we know where your children are, so take that as a threatening message.”

It gets worse: “After about a week,” Boyd explained, “two sets of envelopes were sent to me from Tbilisi, Georgia, containing the same exact same pictures — printout of pictures — that were left in my jacket, but this time the printouts had handwritten messages saying, ‘You touch the wrong girl you pedophile, you think we can’t touch yours?’”

Fusion GPS is led by Glenn Simpson and Peter Fritsch, who left the Wall Street Journal about a decade ago. Boyd provided Fox News with a travel document that Boyd said indicates Fritsch traveled to Venezuela, as part of what he described as an effort to shut down any investigative reporting into Derwick’s actions. Asked if Fusion GPS plays on its credentials as former journalists, Boyd said yes. “I believe that they are basically cashing in on the years of experience they have accumulated collectively in different newspapers, in different media around the world,” he said.

Another victim of Fusion GPS’s smear tactics is Bill Browder, the American businessman who lobbied for tough economic sanctions against Russia known as the Magnitsky Act after his friend and attorney Sergei Magnitsky was tortured and murdered in a Russian jail.

Browder told senators in sworn congressional testimony that Fusion GPS used smear tactics to discredit him and Magnitsky. He also said that Fusion was working on behalf of Russia when it produced the anti-Trump dossier.

To date, Simpson has refused to reveal his sources and who paid for the Trump dossier, with Fusion attorney Joshua Levy threatening in an Oct. 16 letter that Simpson and others will take the Fifth if they are required to appear before the House Intelligence Committee. Defending the company’s work on the Trump dossier, Levy wrote: “Of acute importance, these subpoenas, if indeed directed to our clients, violate the First Amendment rights of our clients and their clients, and would chill any American running for office — regardless of party affiliation, political viewpoint or candidate preference — from conducting confidential opposition research in an election. No individual should be expected to respond to such an abuse of power.” Boyd was dismissive of Fusion’s First Amendment arguments. “I do not believe that certain privileges that apply to journalists and lawyers should apply to Mr. Simpson because he is neither — he’s a spin doctor.”

Boyd told Fox News’ Sandra Smith that they are “con artists … (who) are aiding and abetting criminals.” He added that it was “preposterous” that they would portray themselves as victims in an oped in the New York Times. “I am a victim, my family has been a victim, Bill Browder is a victim,” he said.

“At the end of the day, they have done these things — and there’s a record of them doing these things and being involved in these things. So denying or skirting around the issue is not going to change the story,”

Fusion attorney Joshua Levy failed to respond “to multiple requests for comment” from Fox News about Boyd’s allegations.

Note: A previous version of this article incorrectly stated that Alek Boyd testified before Congress.