WASHINGTON — The Dutch man who claimed to have Marie Yovanovitch under surveillance when she was the U.S. ambassador to Ukraine has been masquerading as a U.S. federal law enforcement officer and told people he was starting a tech company that could track movements electronically, according to interviews and documents obtained by NBC News.

And despite saying he had "no connection" to Ukraine, the man, Anthony de Caluwe, was romantically involved with a Ukrainian woman, who returns regularly to her home country, at the same time in early 2019 that he sent text messages about Yovanovitch's purported whereabouts in Kyiv, according to two people who know de Caluwe and photographs obtained by NBC News.

How de Caluwe, 54, a citizen of the Netherlands and an ardent, vocal supporter of President Donald Trump, ended up sending encrypted messages about Yovanovitch's supposed whereabouts has been mostly a mystery since his name first surfaced in news stories about the Trump administration and Ukraine this month.

Photos from Anthony de Caluwe's Instagram account, 'anthonyfbi,' show de Caluwe in an FBI jacket next to a photo of Donald Trump. via Instagram

Text messages released by the House this month after its impeachment investigation showed that indicted Rudy Giuliani associate Lev Parnas had received cryptic texts about Yovanovitch's movements from Robert Hyde, a Republican congressional candidate in Connecticut, in March 2019, the same period in which Parnas and Giuliani were seeking the ambassador's ouster. Later document releases revealed that Hyde had been the middleman, passing the supposed surveillance details to Parnas from de Caluwe, a fellow Trump supporter he'd met at Republican events.

De Caluwe, who's been living in Belgium and Florida, has posted numerous photos and pro-Trump slogans on his multiple social media accounts, projecting proximity to Trump's orbit with a constant stream of posts that depict Republican events, Trump's Washington hotel and even a Christmas reception at the White House. Sometimes he is clearly at the event pictured, but sometimes he isn't, and he isn't in any pictures that show Trump himself. He has said he's a financial adviser who's never surveilled any Americans, and he has dismissed his encrypted texts claiming to have Yovanovitch under surveillance in March as just "ridiculous banter" with a friend. Trump fired Yovanovitch two months later.

But interviews with a half-dozen people who know de Caluwe and documents obtained by NBC News call into question elements of that story, finding that de Caluwe has a shadowy past — including a history of attacking Yovanovitch on social media, a web of financial companies that appear mainly to be elaborate websites using stock photos, and grandiose plans to begin moving the human race into space.

Two people who know him said separately that they'd grown concerned that he could be a threat to the president because of what they described as a fanatical dedication to Trump. They spoke on condition of anonymity out of concern for their safety. But others who know de Caluwe described him as a fantastical storyteller who, especially after drinking, tended to make up stories that his friends assumed weren't entirely true. They said he was known for seeking investments in various projects he was pursuing that seemed too good to be real.

A photo from Anthony de Caluwe's Twitter account appears to show him at a rally for Donald Trump. via Twitter

No evidence has yet emerged indicating that de Caluwe had a true surveillance operation on Yovanovitch, as he claimed. But the revelations are likely to exacerbate concerns that his text messages may have been more than just a joke.

The FBI has been sharing information with multiple foreign governments regarding de Caluwe, who is currently in Belgium, a source with knowledge of the coordination said. Since his texts about Yovanovitch came to light, the U.S. Embassy in Brussels has reached out to de Caluwe, who is cooperating, a spokeswoman for de Caluwe said.

In the U.S., FBI officials were spotted this month at Hyde's office and home in the days after Hyde's texts about Yovanovitch surfaced. Ukraine and the State Department's Diplomatic Security Service are conducting a joint investigation, with Ukraine's Interior Ministry calling it "necessary for the purposes of clarifying the details of this allegation."

Four people who know de Caluwe said he presented himself when they met as working for the Drug Enforcement Administration. He occasionally told others he was FBI or CIA.

Leland McKee, a Trump supporter and frequent guest at Trump's Mar-a-Lago club, met de Caluwe in Orlando, Florida, in 2018 at the request of a mutual acquaintance. He said de Caluwe wanted him to invest in a "tracking thing" he was developing.

"He said he was with the DEA and all that, law enforcement," McKee said. "He was trying to solicit money from anyone he could get money from, and I knew there was something not quite right."

Anthony de Caluwe. via Facebook

Photos obtained by NBC News also show him wearing what appears to be a DEA badge. One person said de Caluwe flashed the badge when he identified himself to new people as a DEA agent and sought information about drug cases he was purportedly investigating.

DEA spokeswoman Mary Brandenberger said that de Caluwe was never an agent for the DEA. She added that it is against the law to impersonate a federal agent. An FBI spokeswoman declined to comment for this story.

De Caluwe told three people who spoke to NBC News that he'd spent years busting drug rings for the DEA in Latin America, including Venezuela and El Salvador. He told at least two people that his dog, a Dalmatian named Maximus, was trained to sniff out drugs. Photos show that he dressed the dog in a harness identifying it as a DEA police canine.

"Drug ops in South America," Hyde told NBC News, describing what de Caluwe told him he did in the DEA. He said de Caluwe had also represented himself on at least one occasion as a CIA operative. In recent media interviews, Hyde has portrayed himself as a middleman between de Caluwe and Parnas.

De Caluwe has denied Hyde's account and is suing him for defamation. Hyde has said he plans to sue de Caluwe, as well.

Karyn Turk, de Caluwe's spokeswoman, confirmed that he "did work in El Salvador," but she declined to say whether he had worked for the DEA there or elsewhere.

"Any work that he did for the government would be confidential," Turk said. "Our client is always interested in serving the best interest of America and keeping American interests safe."

In his WhatsApp profile, screenshots obtained by NBC News show, de Caluwe identified himself as "Anthony DEA/K9 Unit." He posted numerous photos of himself on social media wearing clothing with DEA and FBI markings, including photos posted on an Instagram account under the handle "AnthonyFBI."

Let our news meet your inbox. The news and stories that matters, delivered weekday mornings. This site is protected by recaptcha

As early as last March, de Caluwe was telling people about a company he was starting that could track people or objects through technology, according to four people who know de Caluwe. That's the same time frame in which Parnas and Giuliani were trying to oust Yovanovitch and de Caluwe was sending messages about her whereabouts to Hyde.

He told several of them that it involved RFID, which uses radio frequencies emitted by small transponders that can be attached to objects to identify and track them from a distance. He also mentioned RFID technology in an online profile that identified one of his projects as "TRACK & TRACE NEW IT TECH COMPANY."

De Caluwe told one of those people that he'd worked for a company whose product lets you track objects with an app. He tried to get the person to install it, but the person said they declined out of concern that de Caluwe would use it to monitor them. Photos obtained by NBC News show that the tracking device was a keychain-size tag consistent with other RFID tracking technologies.

Turk, the spokeswoman for de Caluwe, said the technology "is used to track and locate lost items such as a personal computer or personal electronic device."

"This project was in no way used as surveillance and can't be used as surveillance," she said.

In his text messages to Hyde, released this month by the House, de Caluwe made multiple references to tracking Yovanovitch's whereabouts, including saying her computer and phone were off.

"It's confirmed we have a person inside," de Caluwe told Hyde in one exchange, saying the next day: "Good morning buddy. She had visitors. … Hey brother do we stand down??? Or do you still need intel be safe."

Hyde forwarded to Parnas screenshots of those texts, as well as de Caluwe's question about whether they still needed the ambassador under surveillance. In an interview this month with MSNBC's Rachel Maddow, Parnas said he never took the texts seriously.

Download the NBC News app for breaking news

De Caluwe has changed his story about the texts before. After Hyde initially named him this month as the source of the information he sent Parnas, de Caluwe denied it in emails to NBC News. He said he'd declined to help Hyde with tracking Yovanovitch and had "informed him it's against the law."

But hours later, the House Judiciary Committee released text messages corroborating Hyde's claim that he'd merely passed along the information. De Caluwe then acknowledged that his initial statement had been false. Instead, he dismissed the texts as "just a part of a ridiculous banter" with Hyde that had "no credibility."

"I truly love what the president is doing for America. That is how my friendship with Rob began. I'm apologetic for contributing to any confusion through these communications," de Caluwe said last week.

Trump fired Yovanovitch in May following a smear campaign by Giuliani and his associates. She testified in last year's House impeachment hearings that when Trump fired her, she was told to return on the next plane to the U.S. because of an unspecified concern about her security. A newly disclosed recording from the year before appears to show Trump calling to "take her out" after Parnas alleged that Yovanovitch had denigrated Trump. Parnas has since acknowledged that was false.

Earlier this month, when de Caluwe's text messages about Yovanovitch first emerged, he told NBC News by email that he had "no connection" to Ukraine.

"He has never had any contacts in the Ukraine," Turk, his spokeswoman, added at the time.

But several people with knowledge of de Caluwe's romantic life said he has been involved in 2018 and 2019 with a Ukrainian woman living in Belgium. Photographs obtained by NBC News show de Caluwe and the Ukrainian woman together last March — the same month he sent the texts about Yovanovitch's supposed whereabouts to Hyde.

NBC News is not publicly naming the woman, who has not been implicated in any wrongdoing or involvement in de Caluwe's texts. But court documents and interviews with people who know her portray her as having been born in 1972 in Nelipyne, a city in the former Soviet Union that is now part of Western Ukraine.

A relative of the woman said she returns to Ukraine regularly, sometimes for months at a time. De Caluwe showed pictures of her to people he met in Florida, where he spent parts of 2018 and 2019. NBC News reached out to her through various channels but was unable to reach her. It is unclear whether she traveled to Ukraine during the time she was dating de Caluwe.

Asked about his connection to the Ukrainian woman, de Caluwe's spokeswoman confirmed that they dated and "had a nice time together," but she said de Caluwe no longer speaks to her, adding: "Although she is of Ukrainian descent, this in no way is a direct connection to the country of Ukraine." She said de Caluwe hadn't been to Ukraine.

De Caluwe, whose legal name is Antonius Richard de Caluwe, is a citizen of the Netherlands born in 1965, identification documents reviewed by NBC News show. His spokeswoman confirmed that he's also used the names Anthony Hemelrijk and Anthony Heavenrich — a literal English translation of "Hemelrijk" in Dutch.

Online, de Caluwe claimed to have run a long list of companies involved in private banking, financial advising, real estate development, energy and space exploration. In online biographies, he said he was the president of Eurolink Group Global, ArCosmos and SolarNovo Group, among other companies.

There is no evidence online that any of those entities conducted any actual business, nor was NBC News able to identify any records showing that de Caluwe was registered as a financial or investment adviser in the U.S. Many of the websites for those businesses and their purported subsidiaries are defunct and no longer accessible on the web.

Several individuals who know de Caluwe from his time spent in Florida said he worked to ingratiate himself with wealthy Trump supporters and then sought to leverage those relationships to solicit investments in his business ventures.

In an open letter from de Caluwe posted on several websites, he sought investments in EuroLink Energy Global, which he said had developed a climate change technology that could recycle all garbage from an entire country and turn it into green energy with no carbon dioxide emissions, a process he described as "Waste to Energy."

Much of de Caluwe's social media presence, including photos of him at Trump events, has been scrubbed from the internet since his name emerged as part of the Yovanovitch story. NBC News preserved screenshots of his online profiles before the content was deleted or made private.

A dive through his online presence shows a fixation on Trump and his political movement, with hundreds of photos of pro-Trump paraphernalia and references to slogans like "Make America Great Again" and "Keep America Great."

In 2017, de Caluwe tweeted a screenshot designed to look like a tweet from the president's @realdonaldtrump account, saying: "Anthony Heaven is a true patriot and he doesn't watch fake news. We need more people like him!"

"Heaven" appears to be a truncation of Heavenrich, one of the pseudonyms his spokeswoman confirmed that de Caluwe uses. A review of Trump's actual Twitter feed shows the tweet does not exist there, suggesting that the screenshot tweeted by de Caluwe could have be Photoshopped.

On Nov. 15, the day Yovanovitch testified in the House impeachment hearings and months before de Caluwe's texts about her became public, he posted about her on Facebook and Twitter, saying, "Marie Louise Yovanovitch knows to (sic) much about BO HC and Bidens," apparent references to Barack Obama and Hillary Clinton.

Last year, de Caluwe created a profile on Parler, a social networking site primarily associated with the alt-right and Trump supporters. He tweeted a link to his Parler profile, ADC007, from his Twitter account.

Posts on his Parler profile show that de Caluwe aligned himself with nationalist, anti-immigration themes.

"It will never stop look @ Europe and the UK totally lost their identity as Europeans," he wrote on multiple occasions last year.

De Caluwe also told several people that he had connections high up at NASA and was pursuing space-related projects in partnership with it. His online presence shows a keen interest in space research and projects to colonize the moon or areas in outer space.

He was listed online as a director of the Leeward Space Foundation, whose website says its goals include raising money to "finance space missions, support space exploration and colonization and encourage educational programs related to space exploration and astronomy."

"The first objective of the Foundation will be to support research toward the development, construction, and deployment of earth's first Space Elevator," the website says.

A NASA spokesperson said there's no single database of everyone it does business with, but NBC News found no indications that de Caluwe had any relationship with the agency.

Turk, de Caluwe's spokeswoman, said his purported connection to NASA and the Leeward Space Foundation demonstrate "his interest in space and technology for the further advancement of mankind."

Turk, who began helping de Caluwe with his public response after the story broke in the media, has had her own colorful past in the world of Trump supporters in Florida, where she has held fundraisers for Roger Stone and has also represented Cindy Yang, who found herself in a media storm when a photo of her and Trump surfaced after her day spas were implicated in a scandal involving Robert Kraft, the owner of the New England Patriots.

Turk recently pleaded guilty to a misdemeanor charge of Social Security fraud related to her ailing mother and was sentenced to 30 days in jail. She says she paid full restitution to the government and is appealing the sentence.