House Republican Conference Chairman Liz Cheney, R-Wyo., on Monday pushed for answers on how much top Democrats knew about the explosive White House whistleblower's complaint before it was officially made, after House Speaker Nancy Pelosi's head-turning comments during a televised interview on Sunday.

"He told me it was perfect, that there was nothing on the call," Pelosi said on CBS News' "60 Minutes," referring to a conversation she had with President Trump before the Trump administration released either a transcript of his call with Ukraine's leader or the whistleblower's complaint.

"But, I know what was in the call," Pelosi continued, before quickly adding, "I mean, uh, it was in the public domain."

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Pelosi's remark drew scrutiny from Republicans because no verbatim account of Trump's call had yet been made publicly available.

"@SpeakerPelosi⁩ said on 60 Minutes last night she knew the details of the classified Ukraine call before White House released transcript," Cheney wrote on Twitter. "This is starting to seem like a political set up. So, Madame Speaker, 'what did you know and when did you know it?'”

Speaking to Fox News, Pelosi communications director Ashley Etienne said Pelosi was referring only to publicly available information, and that Cheney had misinterpreted the question Pelosi had been asked. Etienne said that to her knowledge, Pelosi was not made aware of the whistleblower complaint or the contents of the transcript before they were publicly released.

On Sept. 9, House Intelligence Committee Chair Adam Schiff, D-Calif., was informed by the intelligence community inspector general about a whistleblower complaint that could involve the president. The next day, Schiff sent a letter demanding details of the complaint and accusing intelligence officials of violating the law. But Schiff and top Democrats apparently had not obtained a leaked copy of Trump's remarks on his call with Ukraine's leader, which was one of the main focuses of the complaint.

Cheney's comments came as Republicans on Monday challenged intelligence community officials to explain why a key whistleblower form apparently was changed to drop a requirement for "firsthand information," questioning whether the timing was related to the explosive complaint on Trump’s call with the leader of Ukraine.

In a detail first reported by The Federalist, a key form was revised recently to drop a requirement that such complaints include firsthand information in order to be sent to Congress. Although the firsthand requirement was not found in relevant law, it was seemingly an important procedural hurdle -- whistleblowers were required to certify that they had firsthand information, and were told their complaints would not be processed otherwise.

But, in a lengthy statement Monday, the intelligence community watchdog revealed that the whistleblower had said he or she had firsthand information, as well as secondhand information. The watchdog also said the whistleblower had filled out the older version of the form, which retained the requirement that whistleblowers have firsthand information. It remained unclear what the firsthand information was.

The watchdog wrote: "In the process of reviewing and clarifying those forms, and in response to recent press inquiries regarding the instant whistleblower complaint, the ICIG understood that certain language in those forms and, more specifically, the informational materials accompanying the forms, could be read – incorrectly – as suggesting that whistleblowers must possess firsthand information in order to file an urgent concern complaint with the congressional intelligence committees."

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That anonymous complaint, which spurred congressional Democrats to launch an impeachment inquiry last week, was based primarily on secondhand accounts from "more than half a dozen U.S. officials."

The complaint alleged that Trump sought an investigation from Ukraine into the Biden family – something the now-public transcript of the call with President Volodymyr Zelensky confirmed. And, it included a variety of other disputed allegations, including that officials moved to "lock down" records of the call. The White House reportedly started securing call transcripts after the verbatim leaks of the president's calls with the leaders of Australia and Mexico in 2017.

In a letter obtained by Fox News, top House Republicans urged Intelligence Community Inspector General Michael Atkinson to preserve all records related to that revision, allegedly made sometime in August.

Specifically, they questioned whether the timing was related to the Ukraine complaint.

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"When this revised form was published, and whether the whistleblower received a copy of this form when making the disclosure on August 12, 2019, are both unknown to the House Intelligence Committee. However, the timing of the removal of the first-hand information requirement raises questions about potential connections to this whistleblower’s complaint," said the letter signed by House Minority Leader Kevin McCarthy, R-Calif., House Intelligence Committee Ranking Member Devin Nunes, R-Calif., and House Oversight Committee Ranking Member Jim Jordan, R-Ohio. "This timing, along with numerous apparent leaks of classified information about the contents of this complaint, also raise questions about potential criminality in the handling of these matters."

Fox News' Catherine Herridge contributed to this report.