Democrats on the House Judiciary Committee will on Monday ask for more information about a report that the White House counsel asked the Justice Department for an order authorizing surveillance of the Trump campaign, although there’s no evidence that such an order exists.

White House Counsel Don McGahn was reportedly acting on President Donald Trump’s unsubstantiated claim that the Obama White House ordered a wire tap of Trump Tower.

“In our experience, it is highly unusual for the White House to seek access to a government application to the Foreign Intelligence Surveillance Court. In almost any circumstance, it would be inappropriate to ask for that information if the President and his associates are related to the underlying investigation,” the Democrats wrote in a letter to McGahn to be sent on Monday.

The New York Times reported that McGahn had asked the Justice Department to turn over any authorization from the Foreign Intelligence Surveillance Court for surveillance of Trump and his associates, citing a senior White House official. There’s not yet evidence to suggest that any such FISA court order exists, however.

Following criticism that McGahn’s request would breach protocol barring the White House from asking the Justice Department or FBI about such a matter, another Trump administration official told the New York Times that the White House was only looking into whether a legal option exists for it to learn about a FISA court order without interfering in an investigation. The official told the Times that the White House does not know whether any investigation exists.

In their letter, Democrats wrote that reports on McGahn’s request are especially concerning, given previous reporting that White House Chief of Staff Reince Priebus asked the FBI to push back against reports on ties between Trump aides and Russia.

“Perhaps more troubling, this reported contact between your office and law enforcement officials comes on top of several other reports of similar contacts between the White House and both the Department of Justice and the FBI,” the Democrats wrote.

“If these reports are accurate, then these communications are both inappropriate and in violation of Department of Justice guidance. Since the Carter Administration, the Department has had guidelines in place to limit communications between the White House and career investigators and prosecutors, ‘to insure, to the extent possible, that improper considerations will not enter into our legal judgments,'” the Democratic lawmakers added in their letter.

They asked McGhan for information on any contacts between White House staff and the Justice Department or FBI about probes into Russia’s attempts to influence the 2016 election. The lawmakers plan to send a similar letter to the FBI.

The letter will be signed by Reps. John Conyers Jr. (D-MI, pictured above), Jerry Nadler (D-NY), Steve Cohen (D-TN), Hank Johnson (D-GA), Ted Deutch (D-FL), Luis Gutierrez (D-IL), David N. Cicilline (D-RI), Cedric Richmond (D-LA), Ted Lieu (D-CA), Eric Swalwell (D-CA) and Jamie Raskin (D-MD).

This post has been updated.