WASHINGTON — The House committee investigating the Jan. 6 Capitol riot issued a subpoena on Wednesday to Jeffrey Clark, a former Justice Department official under President Donald J. Trump who was involved in Mr. Trump’s frenzied efforts to overturn the 2020 presidential election.
The subpoena seeks testimony and records from Mr. Clark, a little-known official who repeatedly pushed his colleagues at the Justice Department to help Mr. Trump undo his loss. The panel’s focus on him indicates that it is deepening its scrutiny of the root causes of the attack, which disrupted a congressional session called to count the electoral votes formalizing President Biden’s victory.
“The select committee needs to understand all the details about efforts inside the previous administration to delay the certification of the 2020 election and amplify misinformation about the election results,” Representative Bennie Thompson, Democrat of Mississippi and the committee chairman, said in a statement. “We need to understand Mr. Clark’s role in these efforts at the Justice Department and learn who was involved across the administration.”
The subpoena was the 19th issued in the House inquiry, and it came as the panel braced for a potential legal battle with at least one prospective witness, Stephen K. Bannon, a former adviser to Mr. Trump who has refused to cooperate. The leaders of the committee threatened last week to seek criminal charges against Mr. Bannon in response.
Robert J. Costello, a lawyer for Mr. Bannon, did not back down in a letter to the committee on Wednesday, reiterating that his client would not produce documents or testimony “until such time as you reach an agreement with President Trump” on claims of executive privilege “or receive a court ruling.”
On Wednesday, Mr. Thompson said the panel “expects Mr. Clark to cooperate fully with our investigation.”
The Senate Judiciary Committee said last week that there was credible evidence that Mr. Clark was involved in efforts to interrupt the peaceful transfer of power, citing his proposal to deliver a letter to state legislators in Georgia and others encouraging them to delay certification of election results.
The Senate committee also said Mr. Clark recommended holding a news conference announcing that the Justice Department was investigating allegations of voter fraud, in line with Mr. Trump’s repeated demands, despite a lack of evidence of any fraud. Both proposals were rejected by senior leaders in the department.
The New York Times reported in January that Mr. Clark also discussed with Mr. Trump a plan to oust the acting attorney general, Jeffrey A. Rosen, and wield the department’s power to force state lawmakers in Georgia to overturn its presidential election results. Mr. Clark denied the account, which was based on the accounts of four former Trump administration officials who asked not to be named because of fear of retaliation.
The House panel’s subpoena requires Mr. Clark to produce records and testify at a deposition on Oct. 29.
Last week, the committee issued subpoenas to organizers of the “Stop the Steal” rally that took place on the grounds of the Capitol before the violence. The panel has issued subpoenas to 11 others associated with the rallies as well as four allies of Mr. Trump it believes were in communication with him before and during the attack.
Maggie Haberman contributed reporting.