The official was “visibly shaken by what had transpired,” the CIA officer wrote in his memo, one day after Trump pressured President Volodymyr Zelenskiy of Ukraine in a July 25 phone call to open investigations that would benefit him politically.

A palpable sense of concern had already taken hold among at least some in the White House that the call had veered well outside the bounds of traditional diplomacy, the officer wrote.

“The official stated that there was already a conversation underway with White House lawyers about how to handle the discussion because, in the official’s view, the president had clearly committed a criminal act by urging a foreign power to investigate a U.S. person for the purposes of advancing his own reelection bid in 2020,” the CIA officer wrote.

The document provides a rare glimpse into at least one of the communications with a White House official that helped prompt the whistleblower’s formal complaint to the intelligence community inspector general detailing a broad pressure campaign on Ukraine by Trump, administration officials and his personal lawyer.

The complaint and a reconstructed transcript released by the White House formed the basis of the House impeachment inquiry into Trump.

The inspector general, Michael Atkinson, handed the two-page memo over to Congress last week with other documents that shed light on the whistleblower and his actions. A person familiar with their contents, which Fox News first reported, described them to The New York Times. A lawyer for the whistleblower did not comment.

The whistleblower, who relied on “multiple U.S. government officials” for his complaint, said that Trump was “using the power of his office to solicit interference from a foreign country in the 2020 U.S. election.”

It was not clear whether the White House official he spoke to July 26 was the second whistleblower, who has also provided information to Atkinson, or a different person. Neither whistleblower’s name has been made public.

Little, if any, of the whistleblower’s complaint has been disproved, though Trump has sought to discredit him. The White House transcript largely affirmed his account of the call, and Atkinson deemed his complaint credible, saying he interviewed others who corroborated it.

The White House official “seemed keen to inform a trusted colleague within the national security apparatus about the call,” the CIA officer wrote in his July 26 memo.

Much of the whistleblower’s memo also comports with the existing public record of the call between Trump and Zelenskiy. The CIA officer noted that he spoke to the White House official for only a few minutes, “and as a result, I only received highlights.”

The memo detailed key aspects of the conversation, including Trump’s request for investigations into former Vice President Joe Biden and his son Hunter, and a conspiracy theory about Ukrainian meddling in the 2016 election.

Atkinson shared the memo and the other documents with the House Intelligence Committee last week before a session in which he privately described the steps he took to assess the credibility of the complaint.

In submitting his complaint, the whistleblower identified three facts that could be used to accuse him of potential bias against Trump, the documents showed. Two were redacted. The third indicated that the whistleblower is a registered Democrat, a fact first reported by CNN last week that has widely circulated since.

Responding to that reporting on Twitter, Mark S. Zaid, a lawyer for the whistleblower, brushed off the idea that party registration proved anything about his client’s credibility.

“We won’t comment on identifying info but if true, give me a break! Bias? Seriously?” he wrote.

Still, the whistleblower’s political affiliation and the other facts, should they become public, could fuel arguments from Trump and his Republican allies that his actions were politically motivated or that his political views colored how he assessed a string of actions he heard about from other government officials and then summarized in his complaint.

Atkinson’s initial review of the complaint identified some indications “of an arguable political bias on the part of the complainant in favor of a rival political candidate,” he wrote in a letter to the acting director of national intelligence in August. But, he added, “such evidence did not change my determination that the complaint relating to the urgent concern ‘appears credible.’ ”

As part of his complaint, the whistleblower filled out a form, also reviewed by The Times, that asked what other actions, if any, he took in regard to his allegations. The whistleblower checked a box indicating that he had relayed his concerns about Trump to another “office of department/agency involved,” probably a reference to the CIA’s general counsel, Courtney Simmons Elwood. The whistleblower had an intermediary share his allegations with Elwood before he approached Atkinson.

The whistleblower did not check a box indicating that he had spoken to Congress or one of its committees about his allegations. Republicans have seized on that since Fox News revealed it last week, arguing that it is at odds with the CIA officer’s approach to a House Intelligence Committee aide about his concerns before he filed his whistleblower complaint.

It is illegal to intentionally lie on a disclosure form, but whether the whistleblower was justified in omitting his initial contact with Congress probably depends on the substance of the interactions.

The officer approached an aide to Rep. Adam B. Schiff, D-Calif., the Intelligence Committee chairman, with vague outlines of his concern, a spokesman for Schiff has said. The House aide, in accordance with committee practice, encouraged the officer to hire a lawyer to advise him and contact the inspector general. But he also shared some of what the officer conveyed with Schiff, though not his identity.

The whistleblower did not indicate on the complaint form that he had spoken to Congress because he did not disclose the substance of his allegations to the Intelligence Committee, a person familiar with the matter said.