When Donald Trump suggested on Wednesday that Rep. Ilhan Omar (D-MN) once married her own brother in an immigration fraud scheme, he demonstrated the remarkable degree to which even the most far-off corners of the right-wing internet can launch unproven, anonymous claims into the national political discourse.

The president had been asked by a reporter from the pro-Trump One America News Network about whether his administration was investigating Omar “for possibly marrying her brother.” In response, Trump hinted that “somebody” in the government was looking into the matter.

“There’s a lot of talk about the fact that she was married to her brother,” Trump said. “I know nothing about it. I hear she was married to her brother.”

The remarks were the first Trump had ever uttered on Omar’s marriage. And they represented a remarkable—if not depressing—capstone for the unproven rumor, which has gained steam in the fever swamps for three years as Omar became one of the country’s most outspoken and controversial lawmakers.

The claim that Omar married her own brother as a way for him to gain a green card has been embraced by a number of conservative pundits with ties to the president, including commentator Dinesh D’Souza, talk-radio host Rush Limbaugh, and One America host Jack Posobiec. On Thursday, Fox News’ Tucker Carlson discussed it on his show.

Omar, who didn’t respond to requests for comment, has denied that her ex-husband is her brother. And for good reason. What many of the smear’s promoters never reveal to their audience is both the evidence Omar has provided to disprove their conspiracies and the fact that the completely unproven idea that she married her brother is based entirely on a single, anonymous, unsourced allegation initially made on an obscure internet forum.

In August 2016, as Omar was poised to defeat a longtime incumbent from the Democratic-Farmer-Labor Party primary for a state legislature seat in Minnesota, an anonymous post appeared on a Somali diaspora forum called Somali Spot. A user named “AbdiJohnson,” who identified himself in his bio on the site as a Trump supporter, posted a thread called “ILHAN OMAR MARRIAGE FRAUD EXPOSURE.”

In the thread, which has since been deleted from Somali Spot but remains online elsewhere, AbdiJohnson claimed that Ahmed Nur Said Elmi, from whom Omar was then separated, was secretly her brother. Omar had married Elmi, the anonymous poster claimed, in an attempt to make it easier for him to enter the United States.

“What’s even more shocking is that Ahmed Nur Said Elmi is actually her brother,” wrote the user, whose account on Somali Spot has since gone inactive.

AbdiJohnson never provided any evidence for his claim, and searches of Somali Spot posts show that the user was notorious on the site as a troll known for making up claims to rile up the site’s other members. The post was later deleted.

That didn’t stop the claim from getting picked up days later by Minnesota lawyer Scott Johnson, whose conservative Power Line blog became briefly famous in the 2004 election for discrediting forged documents on George W. Bush’s National Guard service. In a post based on AbdiJohnson’s claims, Johnson speculated that Omar, by then the winner of the state legislature primary, had married her own brother in an immigration scheme.

“ Let me note here that Omar’s marriage to her brother, if it occurred in fact, is illegal under Minnesota law. ” — Scott Johnson, Power Line

“Let me note here that Omar’s marriage to her brother, if it occurred in fact, is illegal under Minnesota law,” Johnson wrote.

Johnson has continued to write stories suggesting Elmi is Omar’s brother, writing his latest post about Omar on Thursday. Johnson confirmed to The Daily Beast that the original claim that Omar married her brother was based on the deleted Somali Spot post. Asked to cite the most compelling evidence that Elmi is Omar’s brother, Johnson said only “social-media evidence and [the] sham nature of marriage.”

“She has acted from the beginning like she is hiding something,” Johnson wrote in an email.

After the 2016 Power Line post was published, the claim that Omar had committed immigration fraud and married her brother—which was still based entirely on an anonymous forum post—began to circulate more widely in Minnesota politics. The story was kept alive by Alpha News, a conservative Minnesota politics site with ties to a Republican donor.

Alpha News reporter Preya Samsundar launched a lengthy but inconclusive investigation into various social-media posts, which she claimed “suggests” Omar married her brother. It’s not clear that the social-media accounts scrutinized by Samsundar and her allies, however, even belong to the right Elmi.

Samsundar was hardly a neutral observer or reporter in the matter. She is now a communications staffer for the Minnesota Republican Party and didn’t respond to a request for comment.

Like other promoters of the smear, Samsundar had seized on social-media posts in which someone with Elmi’s name refers to Omar as his “sister.” But according to Somali language experts and language learning websites, “brother” and “sister” can be terms of endearment in Somali that don’t necessarily constitute a familial relationship.

“ It is good manners in Somali culture to use the term ‘brother/sister’ even for cousins and strangers. ” — Bernhard Helander, anthropologist

“It is good manners in Somali culture to use the term ‘brother/sister’ even for cousins and strangers,” anthropologist Bernhard Helander wrote in 1991.

Among the biographical details known about Elmi is that he went to high school in Minnesota and has been described by Omar as a British citizen. Elmi could not be reached for comment for this piece.

But while he did marry Omar in 2009, there has been absolutely no evidence produced to show he is her brother.

Omar’s efforts to disprove the claims have been stymied by the fact that—like earlier right-wing conspiracy theories alleging that Hillary Clinton eats children in a Washington pizzeria or murdered Democratic staffer Seth Rich—her critics never appear satisfied with her explanations. In 2018, Omar showed a reporter from the Star Tribune pictures of immigration documents from when her family entered the United States that list her siblings’ names. The list did not include anyone by Elmi’s name.

“It’s really strange, right, to try to prove a negative,” Omar told the paper. “If someone was asking me, do I have a brother by that name, I don’t. If someone was asking… are there court documents that are false… there is no truth to that.”

The conspiracies around Omar’s marriage have been further fueled by the lack of documents her family has because of their status as refugees from war-torn Somalia, Omar’s reluctance to discuss the smear, and her own complicated marriage history—which critics have used to sow confusion about her marriage.

In 2002, Omar was married in a religious ceremony to a man named Ahmed Hirsi, but the marriage was never legally ratified. In 2008, Omar separated from Hirsi after having two children with him.

A year later, in 2009, Omar legally married Elmi. They separated and religiously divorced two years later, in 2011, but did not legally divorce.

In 2012, Omar was reunited with Hirsi and had another child with him, but did not legally marry him. In 2014 and 2015, Omar and Hirsi filed joint tax returns together, even though she was still married to Elmi.

Though the political significance of this history is confusing, it has shadowed Omar’s pursuit of elected office. As she ran for a Minnesota House position in 2016, the discrepancies between her marriage dates surfaced, and Omar’s campaign paid an accounting firm $1,500 to resolve the joint tax issues. Omar divorced Elmi in 2017 and married Hirsi in 2018. This June, Omar was fined $500 for improperly using the $1,500 in campaign money to resolve the tax issues, providing more fodder for critics looking to allege that there’s something suspicious taking place.

“ Like other implausible claims on the right-wing internet, the Omar rumor has begun to spin off into confusing, lengthy investigations incomprehensible to anyone who hasn’t already read dozens of blog posts. ”

As Omar’s profile grew after her election to the U.S. House in 2018—and after she drew national attention for her criticisms of the Israeli government—higher-profile figures on the pro-Trump internet began to focus on her marriage story. David Steinberg, a writer at conservative blog PJMedia, picked up the investigation and wrote a series of posts suggesting Elmi was Omar’s brother, spreading the idea to a national audience.

Even after the story went outside Minnesota, though, all of the claims continued to rest on anonymous sources. A Steinberg story scrutinizing Elmi’s high-school record has been much praised on the right, for example. But his claim that Elmi and Omar have the same father rests entirely on unnamed people.

In February, anti-Muslim activist Laura Loomer, incompetent conservative operative Jacob Wohl, and Ali Alexander, who would become notorious this June for claiming that Sen. Kamala Harris (D-CA) isn’t an “American Black,” traveled to Minneapolis to “investigate” whether Omar had married her brother.

In between demanding that Omar sign an affidavit swearing she had never married a relative, they portrayed Minneapolis as a dangerous city and asked their fans to pay for their security. Wohl was later caught faking some death threats using a fake Twitter account.

The trio, teaming up with conspiracy theorist Jack Burkman, presented their supposed evidence at the Conservative Political Action Conference in a farcical event. Unable to set up in the conference itself, they were forced to hold their big reveal in the hotel lobby, presenting “confidential” documents that were mainly already reported social-media posts.

Like other implausible claims on the right-wing internet, the Omar rumor has begun to spin off into confusing, lengthy investigations incomprehensible to anyone who hasn’t already read dozens of blog posts.

“ We’re talking about freshman representative Ilhan Omar, who married her brother illegally to arrive in the United States. ” — Rush Limbaugh

Gateway Pundit blogger Jim Hoft, who was invited to the White House last week for Trump’s social-media summit, has attempted to prove Omar entered the country illegally by publishing alleged “facial-recognition” tests that consist of green lines and boxes drawn between former various Somali politicians and Omar’s family. Meanwhile, The Daily Caller and other conservative websites have become fixated on proving that Omar, who said in her divorce filing that she didn’t know how to contact Elmi, actually could have contacted her then-husband—an issue that wouldn’t prove in any way that he’s her brother.

It’s not clear how Trump first became aware of the claims about Omar’s marriage, but the complicated smear has been embraced this summer by a number of right-wing commentators with ties to Trump. In late June, D’Souza, whom Trump pardoned for his campaign-finance crimes, alleged that Omar had married her brother in an immigration-fraud scheme and asked “why hasn’t she been indicted yet?” On Monday, Limbaugh, whom Trump regularly praises on Twitter, told his audience that Omar had married her brother in an immigration-fraud scheme.

“We’re talking about freshman representative Ilhan Omar, who married her brother illegally to arrive in the United States,” Limbaugh said. “But we’re not supposed to mention that because, see, she’s a minority and a woman and they have it so tough anyway.”

Posobiec, a former promoter of the Pizzagate conspiracy theory who has been retweeted by the president, posted an Alpha News video early Wednesday—before Trump’s remarks—that showed a series of unnamed narrators claiming that Omar married her brother.

As with “birther” claims that Barack Obama was born in Kenya, promoters of the Omar smear are using it to strike at the heart of Omar’s status as an American citizen, even though it’s about “her brother” entering the country under false pretenses. Under this impossible theory, they claim it means that Omar abused her own citizenship to get her brother admitted to the country, and will, therefore, somehow have her citizenship revoked.

Trump was a natural ally for this cause, having previously served as the leading birther conspiracy theorist. But instead of trying to lay the foundation for deporting Omar on a seemingly concocted immigration crime, the president has chosen to expedite matters by suggesting she be deported for being too critical of America. Shortly after engaging on the marriage conspiracies on Wednesday, Trump basked in a chant at his rally, in which the crowd called for him to “Send her back!” to Somalia.

On Thursday, he said he didn’t approve of the chant.