Denials of Trump’s previous spying claims have been emphatic.

“As part of that practice, neither President Obama nor any White House official ever ordered surveillance on any U.S. citizen,” an Obama spokesman said in a March 2017 statement following Trump’s first accusation. “Any suggestion otherwise is simply false.”

“Both FBI and NSD confirm that they have no records related to wiretaps as described by the March 4, 2017 tweets,” Justice Department lawyers said in September 2017 court filing that refers to the DOJ’s National Security Division. “FBI again confirmed that they do not have any such records by consulting with personnel knowledgable about Director Comey’s statements and the surveillance activities of the FBI.”

Trump himself admitted last month that he had no evidence to back up his claims.

“I said that just on a little bit of a hunch and a little bit of wisdom maybe [and] it blew up because [people] thought maybe I was wise to them,” he told Fox News’ Sean Hannity.

Trump’s wiretapping claims have paralleled various stories about Mueller’s investigation into his campaign’s contact with Russia. On Thursday, Mueller’s office released information that former national security adviser Michael Flynn provided to the investigation. Flynn in 2017 pleaded guilty to lying to the FBI about his contacts with Russia.

The Mueller report, released last month, did not charge Trump with crimes related to Russian collusion. However, it indicated that the campaign “expected it would benefit electorally from information stolen and released through Russian efforts.”

Mueller did not charge Trump with obstruction of justice, though he did not exonerate the president. In addition to Flynn, five other former Trump advisers or officials have been implicated in the probe.