Last month, the Lincoln Project said it was “shocked” by accusations that the anti-Trump group’s co-founder, John Weaver, had sexually harassed multiple young men.

Now, the group says it is hiring an outside investigator to probe what it called Weaver’s “appalling conduct and … abuse,” a move that came after the Associated Press reported that its leadership was actually aware for months about the allegations against Weaver.

The move did little to calm backlash against the group, though, after its Twitter account late on Thursday published — and then quickly deleted — private conversations between journalist Amanda Becker and Jennifer Horn, a Lincoln Project co-founder who left following the accusations against Weaver. Horn said the messages were published without her permission, and the 19th, a nonprofit newsroom reporting on gender, politics and policy, vowed to continue its reporting on the group.

“We’re not going to be bullied or intimidated out of pursuing critical journalism,” tweeted Emily Ramshaw, co-founder and CEO of the 19th.

The Lincoln Project did not immediately respond to a message from The Washington Post seeking comment about the deleted tweets as of early Friday.

The incident is the latest turmoil facing the group, which gained momentum last year with viral ads attacking President Donald Trump and his supporters, becoming among the best known “Never Trump” organizations and raising millions of dollars.

But in early January, Weaver, a longtime GOP strategist who previously worked on the presidential campaigns of John McCain and John Kasich, was accused in an American Conservative piece of making unsolicited sexual advances to young men, including one as young as 14.

Weaver, who had taken a medical leave from the Lincoln Project, told Axios last month that he would not return and apologized for sending “inappropriate” messages.

“The truth is that I’m gay and that I have a wife and two kids who I love,” Weaver, 61, told Axios. “My inability to reconcile those two truths has led to this agonizing place.”

On Jan. 31, 21 men who spoke to the New York Times said Weaver had harassed them and pressured them for sex in exchange for professional advancement.

After that report, the Lincoln Project condemned Weaver, calling him a “predator,” “liar” and “an abuser.” The group said it had been caught off-guard by the allegations, saying in a statement, “Like so many, we have been betrayed and deceived.”

But Ryan Girdusky, the American Conservative reporter who broke the news of the allegations, called the group’s response “false,” noting that Weaver’s behavior was like a “worst-kept secret,” The Post’s Amy B Wang reported.

Steve Schmidt, a co-founder of the group, told the Times that “chatter” about Weaver having relationships with younger men had reached the Lincoln Project leaders last summer. But he denied they knew about his inappropriate behavior.

Those claims came into question on Thursday, when the Associated Press reported that leaders of the organization were notified in June of at least 10 harassment claims against Weaver, including two involving Lincoln Project employees.

The group refuted those reports, calling them stories “filled with inaccuracies” and “incorrect information,” but also announced that it would hire an independent investigator to look into allegations against Weaver. The group also encouraged anyone who has a nondisclosure agreement and wanted to speak about Weaver to get a release. At least six former employees and associates have asked to be released from such agreements, the Times reported Thursday.

“John Weaver betrayed all of us and you deserve the facts presented independently through a transparent process,” the group said in a Thursday statement.

Soon, the group was back under fire again, though, for posting the private conversations between Horn and Becker.

“Hey @Twitter @jack @TwitterSupport I did not give consent,” Horn tweeted.

Last week, the Lincoln Project announced Horn no longer belonged to the group, alleging she had requested an immediate “signing bonus” payment of $250,000 and a $40,000 per month consulting contract, which the management committee and the board rejected. The group said it had accepted Horn’s resignation.

Horn disputed the claims in a statement citing the group’s reluctance to properly address the allegations against Weaver, which she said she was unaware of prior to the news reports.

“I was genuinely shocked," Horn said. “These are not my stories to tell, but I knew in that moment that the Lincoln Project had an opportunity to take a stand and do better.”

Wang contributed to this report.