New York CNN  — 

Attempts to undermine Sen. Kamala Harris’ racial identity had been festering on conspiratorial corners of the internet for months before being elevated to the mainstream by Donald Trump Jr. during last week’s debate, an expert that tracks online misinformation tells CNN.

In addition to efforts to undermine Harris’ identity as a black woman, a false claim that Harris is not eligible to run for president because both of her parents are foreign-born has also been circulating. The claim has echoes of the false birther conspiracy that was spread about President Barack Obama – and some of the same people involved in spreading that conspiracy are involved in circulating the false claims about Harris.

Soon after Harris’ debate-defining moment when she recounted being bused to school as a little girl, a swarm of Twitter accounts, many anonymous, began spreading disinformation about the senator’s race.

“You. Are. Not. Black,” one Twitter user, who was suspended from the service the following morning, tweeted at Harris soon after the California senator confronted former vice president Joe Biden about his comments on working with segregationist senators and his past opposition to busing.

Trump Jr. amplified those attacks when, on Thursday, he shared a tweet sent by one user with the assertion, “Kamala Harris is *not* an American Black. She is half Indian and half Jamaican.”

“Is this true? Wow,” Trump Jr. asked along with the shared tweet. He later deleted his tweet. A spokesman for Trump Jr. told The New York Times that there had been a misunderstanding.

“Don’s tweet was simply him asking if it was true that Kamala Harris was half-Indian because it’s not something he had ever heard before,” Andy Surabian, the spokesman told The Times, adding, “and once he saw that folks were misconstruing the intent of his tweet, he quickly deleted it.”

Over the weekend, Harris’ campaign and some of her Democratic opponents condemned the attacks.

“This is the same type of racist attack his father used to attack Barack Obama,” Lily Adams, the campaign communications director for Harris, told CNN. “It didn’t work then and it won’t work now.”

Benjamin T. Decker, the founder of Memetica, a digital investigations consultancy, tracked a meme that tries to equate Harris to Rachel Dolezal, a white woman who portrayed herself as black.

Decker began tracking the online conversation about Harris after she announced her candidacy in January. At the time, Decker was a fellow at Harvard’s Shorenstein Center studying online misinformation and the proliferation of extremist content across social media.

Decker said the first instance of the meme he found online was from 2018 on the “The_Donald,” a forum for Trump supporters on Reddit. The forum has been embraced by Trump and his circle, but last week Reddit “quarantined” the forum because of what it said were “threats of violence against police and public officials.”

He then tracked how the meme spread across Twitter, Pinterest, 4chan and other platforms, writing about it for Politico earlier this year.

“By comparing Harris to Rachel Dolezal the meme creators tried to stoke identity falsehoods about Harris ‘blackness’ as well as suggesting that she is hiding the truth about who she is,” Decker told CNN on Monday.

Birther conspiracy theorists have also circulated material challenging Harris’ eligibility to run for president. Harris, who was born in Oakland, California, is eligible to run for president.

“The adversarial attack on Harris’ eligibility highlights how political disinformation operators recycle narratives that have had success in the past with hyper-partisan communities,” Decker explained, adding that some of the main architects of the birther conspiracy against Obama are utilizing social media to spread similar falsehoods about Harris.

A Twitter spokesperson told CNN Sunday that accounts attacking Harris’ race during the debate were not automatic “bots.”

“We saw no coordinated use of automation during recent debates,” a Twitter spokesperson said.

But Decker said that even without the use of automated accounts, it was possible that individuals coordinated to spread the attacks. Automation, he said, is easier to detect, while groups of Twitter users coordinating to spread a smear is more difficult and presents an even more difficult challenge for Twitter.

Harris has previously answered those who have questioned her black heritage.

In an interview with The Breakfast Club hosts DJ Envy and Charlamagne Tha God that aired in March, the show’s hosts asked the California Democrat to address a series of derogatory memes that have circulated on social media. One of the hosts cited a meme that said Harris is “not African-American” because her parents were immigrants and she spent her high school years in Canada.

“So I was born in Oakland, and raised in the United States except for the years that I was in high school in Montreal, Canada,” Harris responded at the time with a laugh. “And look, this is the same thing they did to Barack (Obama). This is not new to us and so I think that we know what they are trying to do.”

“They are trying to do what has been happening over the last two years, which is powerful voices trying to sow hate and division, and so we need to recognize when we’re being played,” Harris said.