House Intelligence Committee chairman Devin Nunes, R-Calif., has sent a letter to Deputy Attorney General Rod Rosenstein and FBI Director Christopher Wray demanding an uncensored copy of the document the bureau used to formally begin its investigation into alleged collusion between Russia and the President Trump campaign.

The origination document has been the subject of much controversy. After some Republicans alleged that the FBI used never-verified parts of the Trump dossier as part of its reason to begin the investigation in July 2016, some “current and former” officials leaked to the New York Times that no, it was the case of George Papadopoulos, reported to U.S. authorities by foreign intelligence agents, that prompted the FBI investigation.

“The information that Mr. Papadopoulos gave to the Australians answers one of the lingering mysteries of the past year: What so alarmed American officials to provoke the FBI to open a counterintelligence investigation into the Trump campaign months before the presidential election?” the Times reported on December 30. “It was not, as Mr. Trump and other politicians have alleged, a dossier compiled by a former British spy hired by a rival campaign. Instead, it was firsthand information from one of America’s closest intelligence allies.”

Citing the subpoena from last August, Nunes directs Rosenstein and Wray to produce “an unredacted version of the EC” to the committee by April 11. “Be advised that failure to comply in a satisfactory manner will result in the committee pursuing all appropriate legal remedies, including seeking civil enforcement of the August 24 subpoenas in federal district court.”

READ MORE: