Sens. Chuck Grassley, R-Iowa, and Lindsey Graham, R-S.C., this week pressed the Democratic National Committee and Hillary for America for details and documents related to the work of “Trump dossier” author Christopher Steele, amid concerns that the FBI may have used information in the dossier to seek authorization for surveillance of Trump associates.

“The Senate Judiciary Committee has a constitutional duty to conduct oversight of the FBI and broader Department of Justice,” the senators wrote in letters sent Thursday that went public on Friday. “Part of that duty involves ensuring that law enforcement efforts are conducted without improper influence.”

“The scope of our review includes the extent to which the FBI may have relied on information relayed by Mr. Steele in seeking judicial authorization for surveillance of individuals associated with Mr. Trump,” added Grassley, who is chairman of the Senate Judiciary Committee, and Graham, the chairman of the panel’s subcommittee of crime and terrorism.

Fusion GPS, a Washington opposition research firm, was funded in part by the Clinton campaign and DNC lawyer Mark Elias to oversee the research. Fusion GPS then hired former British intelligence officer Steele, who wrote the dossier, which contains salacious and unverified claims about President Trump's ties to Russia.

The senators said they want to determine if applications seeking permission for surveillance accurately disclosed the source of Fusion GPS’s and Steele’s funding, the extent to which the assertions were or were not verified, and motivations of Steele and his clients and sources.

Additionally, they are seeking documents to understand who from the DNC and the Clinton campaign were aware of Steele’s efforts on behalf of the DNC and campaign to disperse content from the dossier, whether members from either group received information contained in the dossier prior to its publication, and if Clinton was informed about Steele’s efforts and the allegations “he was spreading.”

The letter also asks for answers about whether the DNC and campaign were aware of Steele’s contacts with “the FBI or other agencies prior to the 2016 election.”

Grassley and Graham wrote that they want a reply by Feb. 8.

In addition to the DNC and Hillary for America, letters were sent to former DNC chair Rep. Debbie Wasserman Schultz, D-Fla., former DNC chair Donna Brazile, Hillary for America chair John Podesta, and Hillary for America chief strategist Joel Benenson.

Some aspects of the dossier — like communications between foreign nationals noted in the dossier — have been confirmed by officials; however, the majority of the scandalous allegations included in the document have not been verified.

The dossier came to light publicly after it was published in full by Buzzfeed in January.

The letters from Grassley and Graham come after some members of Congress viewed a memo organized by by House Intelligence Committee Chairman Devin Nunes, R-Calif., which allegedly outlines surveillance violations by the U.S. government.

Dozens of House Republicans have rallied for the memo to be publicly released and claim it contains evidence of violations of the Foreign Intelligence Surveillance Act. The memo, which describes classified material from the FBI and Justice Department, reportedly says incorrect statements from Steele about Trump associates’ connections to Russia were included in an approved application to put Carter Page, a Trump campaign official, under surveillance.

However, current and former law enforcement officials have said other information was also used to justify the surveillance application.

The DOJ on Thursday warned Nunes against releasing the memo concerning Foreign Intelligence Surveillance Act, or FISA, calling it “extraordinarily reckless," without giving the DOJ and FBI the opportunity to review it and to advise the committee "of the risk of harm to national security and to ongoing investigations that could come from public release.”

On the other side of the aisle, Democrats have brushed of the information in the memo and called it “talking points” that are leading a “false narrative."

Democrats from the intelligence committee this week announced they are putting together their own memo to refute the Nunes memo.