A senior Justice Department official told BuzzFeed News that the final decision on whether to open a campaign finance investigation into the Zelensky call was made by Benczkowski. Meanwhile, The Associated Press reported that Demers was made aware of the complaint on Aug. 14, and CNN reported that Engel was responsible for determining if the whistleblower complaint was an "urgent concern."

As part of their hearing request, Democrats noted that Trump mentioned the attorney general specifically in his call with Zelensky. The committee, according to Democrats, should look into the "full extent" of Barr's involvement "with Ukraine and matters related to the whistleblower’s complaint."In addition to Barr, Democrats want Assistant Attorney General Brian Benczkowski, Assistant Attorney General Steven Engel and Assistant Attorney General John Demers to be called to testify.

"Those documents raise additional concerns that the White House has known about and, potentially aided by top officials at the Department of Justice, may have taken steps to conceal presidential misconduct," they wrote.

In a letter to Graham, the 10 Democrats on the panel argued that the committee has "an important leadership role to play" as lawmakers dig into a whistleblower complaint and the July 25 phone call in which Trump urged Ukrainian President Volodymyr Zelensky to look into former Vice President

Democrats on the Senate Judiciary Committee are pressing Chairman(R-S.C.) to call Attorney Generaland other senior officials to testify about's actions on Ukraine.

They also want White House counsel Pat Cipollone to testify about the White House's use of nondisclosure agreements and for Inspectors General Michael Atkinson and Michael Horowitz, the top watchdogs for the intelligence community and the Justice Department, respectively, to testify.

The decision by Democrats to step up their demands for hearings tied to the complaint and Trump's call with Zelensky comes after Trump reportedly said that whoever gave information to the whistleblower is "close to a spy."