Twitter said Thursday that it would not scrub its platform of a conspiracy theory falsely tying Beto O’Rourke, a Democratic presidential aspirant and former Democratic congressman, to the gunman who killed seven people in two west Texas towns on Saturday because the posts did not run afoul of the company’s policies.

“As of this time, it doesn’t constitute a violation of our rules,” a representative for the social media giant said.

Among the users amplifying the smear against O’Rourke was Anthony Shaffer, a former Defense Intelligence Agency officer and a member of Trump’s 2020 advisory board, which the campaign said was a “diverse group of key supporters committed to reelecting President Donald Trump.”

“Advisory Board members often serve as surrogates in media appearances or by writing op-eds,” the campaign added in a statement provided this week.

Shaffer, who has promoted baseless claims about the 2012 attacks in Benghazi, Libya, and clashed with the U.S. military and intelligence communities over his allegations of an intelligence failure before the attacks of Sept. 11, 2001, took to Twitter after the Saturday shooting in Odessa and Midland to mock Democrats for demanding new restrictions on firearms.

In one tweet, he said the gunman was a supporter of O’Rourke, tagging the presidential candidate and retweeting a post from an account with the handle @suemo54 and the name “Sue Moore.”

The original tweet, posted Sunday, read: “The Odessa Shooter’s name is Seth Ator, a Democrat Socialist who had a Beto sticker on his truck.”

“No,” said Oscar Villarreal, a spokesman for the Texas Department of Public Safety, when asked whether those assertions held water. The claim, which was retweeted more than 11,000 times by Thursday evening, appears to have been significantly amplified by bot accounts, said Nir Hauser, a co-founder of a firm called VineSight, which uses artificial intelligence to track misinformation.

Twitter confirmed that it was looking into the tweet on Wednesday. On Thursday, a representative said the company would leave the original post, as well as the endorsement from the Trump surrogate, untouched.

The social media giant says it monitors for large-scale ma­nipu­la­tion — and acts when it detects such broadly coordinated activity — while also barring abuse, harassment and threats of violence, among other types of behavior sketched out in its rules. Otherwise, the company maintains it cannot act as an arbiter of truth.

That stance incensed O’Rourke’s campaign manger, Jen O’Malley Dillon, who on Tuesday said on Twitter that social media companies weren’t doing enough to root out misinformation.

“As a campaign, we’re almost entirely powerless to stop misinformation. We can tweet corrections, but only a fragment of the people exposed will see it,” she said. “This rests on Twitter, Facebook, and Google who let this go completely unchecked.”

In a statement to The Washington Post, O’Malley Dillon said the platforms were enabling the same type of misbehavior that Russia employed in its effort to sway the 2016 presidential election.

“This is what Trump, with Russia’s help, did in 2016, and as bots spread misinformation and sow divisions in our country once again, this administration refuses to do anything about it,” she said. “These companies claim to be powerless to stop false stories like these from spreading — but their employees are the most sophisticated engineers on the planet, capable of rooting out all kinds of nefarious content from their platforms.”

Democratic National Committee staffers alerted O’Rourke’s campaign to the conspiracy theory on Monday morning. By Tuesday, it had spread across Twitter and Facebook, garnering thousands of shares, and, according to the campaign, was the second highest-trending search query related to the candidate in the previous seven days. As of Thursday, only Google had contacted O’Rourke’s staff to discuss the matter.

Sue Moore’s account, which appears to have hatched the conspiracy theory about O’Rourke, identifies its owner as a 72-year-old retiree living in Mesa, Ariz. A message left on a linked Facebook page went unanswered this week.

Shaffer, in a brief phone interview, said he has served on Trump’s advisory board “since the time they went into office.” He said the post was unpaid.

When informed that the information he had shared on Twitter was false, he responded, “That’s not what I’ve seen from people.”