Rod Rosenstein, the deputy attorney general tasked with drafting a memo to explain the removal Tuesday of FBI Director James Comey, threatened to resign after he was painted by the Trump administration as the mind behind the firing, according to The Washington Post.

The Post, citing an anonymous source close to the White House, said Rosenstein felt like he was “cast as the prime mover of the decision to fire Comey,” when in fact he was asked by administration officials to draft the memo after President Donald Trump had already decided to fire the FBI director.

Rosenstein wrote a three-page memo that detailed Comey’s unorthodox handling of the investigation into Democratic presidential candidate Hillary Clinton’s use of a private email server while secretary of state. He noted that Comey’s actions caused “substantial damage” to the reputation of the FBI. Though he didn’t specifically call for the director’s firing, he unequivocally stated that the way Comey handled the email inquiry was “wrong” and said the bureau would be hard pressed to regain credibility under current leadership.

“As a result, the FBI is unlikely to regain public and congressional trust until it has a Director who understands the gravity of the mistakes and pledges never to repeat them,” Rosenstein wrote.

Trump’s formal letter dismissing Comey pointed specifically to Rosenstein’s memo and ultimately said the FBI director was “not able to effectively lead the bureau.” Vice President Mike Pence, speaking to CNN, also said the decision was based on Rosenstein’s memo.

The Post reports some have been confused by the attention given to Rosenstein, and many of his colleagues said the lack of a direct call to fire Comey may have been an effort to push back without getting fired himself. CNN portrayed the career Justice Department official as an “unlikely hatchet man,” which left some wondering if he acted on his own or on the White House’s orders.

Critiques over his involvement, however, continue. In an open letter published Thursday by The New York Times, its editorial board cast Rosenstein’s involvement as “mere pretext” for Trump’s firing, which many have instead linked to the FBI’s ongoing investigation into Trump campaign links to the Russian government.

“We can only hope that your lack of an explicit recommendation to fire Mr. Comey reflects your own refusal to go as far as the president wanted you to,” the editorial said.

Sarah Isgur Flores, the top spokeswoman at the DOJ, denied that Rosenstein threatened to resign. “Didn’t happen,” she wrote to HuffPost on Thursday. This article has been updated with comment from Flores.