President Donald Trump affirmed in written responses to “key” questions posed by special counsel Robert Mueller that he had no prior knowledge of the June 2016 Trump Tower meeting, according to CNN.

Additionally, the president told Muller that political operative Roger Stone did not relay information about WikiLeaks ahead of the self-described non-profit media organization’s email dump during the presidential election. In a previous interview with the Associated Press, the president denied knowing of the organization’s existence. “When WikiLeaks came out … never heard of WikiLeaks, never heard of it,” the president said. “When WikiLeaks came out, all I was just saying is, ‘Well, look at all this information here, this is pretty good stuff.'”

Mueller’s team believes former Infowars D.C. bureau chief tipped off Stone months before WikiLeaks released thousands of emails stolen from Hillary Clinton’s campaign chairman, according to documents.

One of the documents, which was drafted as part of a plea offer to Corsi, provides an unprecedented window into an active part of Mueller’s investigation into Russian election interference and possible coordination with Trump associates. It reveals that Mueller is keenly focused on whether Americans close to the Trump campaign had any foreknowledge of WikiLeaks’ plans to release hacked material during the 2016 presidential campaign.

The document’s contents were first reported by NBC News, and a copy of it was posted online by The Washington Post. Corsi told The Associated Press on Tuesday evening that the document had been provided to his attorney by Mueller’s team. Stone has denied knowing about WikiLeaks plans’ ahead of time. Mueller spokesman Peter Carr declined to comment.

Corsi said the document, which mirrors similar ones filed by Mueller in previous plea deals, contains portions of emails he exchanged with Stone in the summer of 2016 about WikiLeaks. But he denied that he intentionally lied to investigators about the emails, and said that was why he rejected the plea offer, which would have charged him with one count of making false statements.

Mueller’s team also has been investigating the 2016 Trump Tower meeting, which occurred weeks after Trump had clinched the Republican presidential nomination and which his son attended with the expectation of receiving damaging information about Democrat presidential nominee Hillary Clinton. A grand jury has already heard testimony about the meeting, which in addition to Donald Trump Jr., also included Jared Kushner, President Trump’s son-in-law, and his then-campaign chairman Paul Manafort.

The White House initially said the meeting, which also involved a Russian lawyer who for years has advocated against U.S. sanctions of Russia, was primarily about an adoption program, yet days after the story was published, Trump Jr. released emails showing he took the meeting after being told he would receive damaging information on Clinton. Mueller’s investigation has included scrutiny of the White House’s drafting of the initial incomplete statement.

On July 27, President Trump said he had no prior knowledge of the meeting, tweeting: “I did NOT know of the meeting with my son, Don jr. Sounds to me like someone is trying to make up stories in order to get himself out of an unrelated jam.”

…..I did NOT know of the meeting with my son, Don jr. Sounds to me like someone is trying to make up stories in order to get himself out of an unrelated jam (Taxi cabs maybe?). He even retained Bill and Crooked Hillary’s lawyer. Gee, I wonder if they helped him make the choice! — Donald J. Trump (@realDonaldTrump) July 27, 2018

The Associated Press contributed to this report.