President Donald Trump. Drew Angerer/Getty Images

Donald Trump is facing the biggest firestorm of his presidency in large part because of his own staff.

A whistleblower who filed a complaint accusing Trump of abuse of power and wrongdoing said they learned of Trump's conduct from "multiple White House officials with direct knowledge of" a phone call between Trump and Ukrainian President Volodymyr Zelensky, which is at the heart of the complaint.

The whistleblower said they heard "various facts related to" it from more than half a dozen US officials. "Multiple officials recounted fact patterns that were consistent with one another," the complaint said.

The complaint said White House officials who informed the whistleblower of Trump's call were "deeply disturbed" by what they had heard. They also told the whistleblower that White House lawyers were already discussing how to handle the call because they believed they'd witnessed Trump "abuse his office for personal gain."

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Donald Trump is weathering the biggest firestorm of his presidency thanks largely to his own staff.

At the center of the controversy is a whistleblower complaint that a US intelligence official filed against Trump in August. The complaint, which was released to the public on Thursday, focuses primarily on Trump's July 25 phone call with Ukrainian President Volodymyr Zelensky in which Trump repeatedly pressured Zelensky to investigate former Vice President Joe Biden ahead of the 2020 election and to help discredit the Russia investigation.

The complaint alleged that Trump's personal lawyer Rudy Giuliani was a key figure in the push and that Attorney General William Barr "appears to be involved as well." It said Trump urged Zelensky to "meet or speak with two people the President named explicitly as his personal envoys on these matters, Mr. Giuliani and Attorney General Barr, to whom the President referred multiple times in tandem."

Notably, the whistleblower said they were not a direct witness to the conduct described in the complaint or to Trump's conversation with Zelensky but learned of it from "multiple White House officials with direct knowledge of the call."

The whistleblower said they heard "various facts related to" it from more than half a dozen US officials. "Multiple officials recounted fact patterns that were consistent with one another," the complaint said.

The complaint said White House officials who informed the whistleblower of Trump's call were "deeply disturbed" by what they had heard. They also told the whistleblower that White House lawyers were already discussing how to handle the call because they believed they'd witnessed Trump "abuse his office for personal gain."

Read more: Acting DNI Joseph Maguire is testifying to Congress about an explosive whistleblower complaint against Trump

Trump and his allies have repeatedly alleged that the whistleblower learned details about the call because someone within the intelligence community leaked them.

But the acting director of national intelligence, Joseph Maguire, told the House Intelligence Committee on Thursday that the whistleblower likely got the information from Trump's own staff.

Republican Rep. Devin Nunes asked Maguire whether it was "normal for the president of the United States to have their conversations" with foreign leaders "leak out."

"This is the third time," Nunes said.

"I wouldn't say the White House, but there are individuals within the White House that may or may not," Maguire said. "I don't know. But it would not be from an intelligence intercept, I will say that."

Nunes also suggested that someone within the intelligence community was responsible for leaking information about the complaint to the media before the document was released to the public on Thursday.

"What I'm trying to ascertain is how would it run in all the mainstream media outlets?" Nunes said of the complaint. "Even though they got a lot of it wrong, but they had the basics of it, that it involved the president of the United States talking to a foreign leader. So did anybody - you or anybody in your office - leak this to The Washington Post or NBC News?"

"Ranking member, I lead the intelligence community - we know how to keep a secret," Maguire said. "As far as how that got into the press, I really do not know, sir."

Executive-branch officials routinely listen in on the president's phone calls to take notes, which are shared with government agencies tasked with carrying out the president's policies.

Maguire added that "it was not from the intelligence community, from me, or from my office."

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