President Trump reportedly held on to a resignation letter from then Attorney General Jeff Sessions after telling him he could stay in the role, a move that advisers worried could be used to influence the Justice Department.

According to special counsel Robert Mueller’s report, after finding out that a special counsel had been appointed, Trump became upset with Sessions and said he should resign. Trump was angry that Sessions had recused himself from the investigation.

The next day, May 18, 2017, Sessions handed Trump a resignation letter that read: “Pursuant to our conversation of yesterday, and at your request, I hereby offer my resignation.”

Trump repeatedly asked Sessions if he actually wanted to stay in the role. Sessions said that he did, but noted that it was up to Trump. Trump said he decided he wanted him to remain as attorney general, but didn’t return the resignation letter, instead putting it in his pocket before Sessions left.

When then-chief of staff Reince Priebus and former senior adviser strategist Steve Bannon found out that Trump was holding on to Sessions’ resignation letter they worried it could be used to influence the Justice Department.

Priebus told Sessions that it was a bad move because the letter could act as a kind of “shock collar” that Trump could use whenever he wanted and said that Trump had the “DOJ by the throat.” Both Priebus and Bannon told Sessions they would try to retrieve the letter.

Then-communications director Hope Hicks told Mueller’s team that, during a trip to the Middle East the next day, Trump pulled the letter from his pocket and asked a group of senior advisers what he should do with it. During that trip, Priebus asked about the letter, but Trump told him that he had left the letter back at the White House.

On May 30, Trump returned the letter to Sessions with a note saying, “Not accepted.”

[ Opinion: Mueller report reveals those surrounding Trump protected him from his own worst instincts]