Congressional investigations into the attempted assassination of former President Trump are moving swiftly across six committees in two chambers, with several groups of lawmakers receiving private briefings Monday and a public hearing coming next week.

The House Oversight Committee on Monday announced that Secret Service Director Kimberly Cheatle will appear at a hearing on Monday, July 22. Committee Chair James Comer (R-Ky.) had sent a request over the weekend for her to testify.

“The United States Secret Service has a no-fail mission, yet it failed on Saturday when a madman attempted to assassinate President Trump, killed an innocent victim, and harmed others,” Comer said in a statement, adding that while he is “grateful to the brave Secret Service agents … questions remain about how a rooftop within proximity to President Trump was left unsecure.”

In preparation for the hearing, Comer and every Republican on the panel on Monday sent the Secret Service a request for various documents, communications and other information regarding the security preparations for the rally.

In addition, the Oversight panel has a member briefing scheduled with the Secret Service for Tuesday, a source familiar with the matter told The Hill.

Cheatle said in a statement Monday that the agency “will also work with the appropriate Congressional committees on any oversight action.”

Over in the House Homeland Security Committee, Chair Mark Green (R-Tenn.) and ranking member Bennie Thompson (D-Miss.) had a “detailed call” with FBI Executive Assistant Director Robert Wells on Monday afternoon, a committee spokesperson said.

In the call, the committee leaders were told that the FBI’s Pittsburgh office is leading the investigation into “potential domestic terrorism and the attempted assassination of President Trump.” While the FBI is focused on the gunman and his motive, the Secret Service is conducting a separate review of its security protocol.

They were also told that the FBI has conducted nearly 100 interviews so far and has access to the gunman’s phone, which “pleased” Green.

The suspected shooter, 20-year-old Thomas Matthew Crooks, was shot and killed by Secret Service agents moments after he opened fire. Trump said in a statement that a bullet had “pierced” his right ear. One rally attendee died, and two others were critically injured.

Green received assurances about transparency in the investigation, and hopes to schedule a site visit once the scene had been processed, the spokesperson said.

Green over the weekend sent a request to Homeland Security Secretary Alejandro Mayorkas for documents and communications about the security plans for Saturday’s Trump rally, including those relating to any potential increase of security resources for Trump, referencing reports that the department had “rebuffed” requests for additional security for Trump.

A Secret Service spokesperson on Sunday had disputed those reports as “untrue” and “absolutely false,” and said that the Secret Service had added resources and protective capabilities as Trump increased his campaigning.

While a member briefing with the Secret Service director will be rescheduled, Cheatle did speak to Green on Sunday, in which he detailed his current information requests.

Leaders in the House Judiciary Committee also received a briefing from the FBI on Monday morning, and House Intelligence Committee Chair Mike Turner (R-Ohio) was also briefed by the FBI on Monday, sources confirmed to The Hill. 

Investigations are underway in the Democratic-controlled Senate, as well.

Sen. Gary Peters (D-Mich.), the chair of the Senate Homeland Security and Government Affairs Committee, announced that his panel will pursue a bipartisan investigation on the assassination attempt.

“We’re going to be doing … a bipartisan investigation from the Committee on Homeland Security to look at the events that occurred and determine whether or not there were security breaches that we need to close,” Peters told reporters at the Capitol on Monday, adding that he spoke “at length” with Mayorkas on Sunday.

Peters said he would try to “expedite” a hearing on the shooting, in response to members like Sen. Rick Scott (R-Fla.) calling for officials to testify before the August recess.

Senate Judiciary Committee ranking member Sen. Lindsey Graham (R-S.C.) and the Republicans on the committee, meanwhile, are pressing Senate Judiciary Committee Chair Dick Durbin (D-Ill.) to hold a hearing with Cheatle, Mayorkas and FBI Director Christopher Wray.

“We hope to work with you to investigate this matter publicly, and to bring answers and confidence in our system to the American people,” the Senate Judiciary Committee Republicans wrote.

Durbin, meanwhile, was briefed on the investigation into the shooting on Monday by the FBI’s deputy director, a source told The Hill, and has requested a closed-door, in-person briefing with the Secret Service, the Department of Homeland Security and FBI for all the panel’s members when the Senate returns to session next week. Discussions are also underway with the Republican minority about possible next steps, including a hearing.

One lawmaker, Rep. Jeff Duncan (R-S.C.), is calling to establish a central independent commission to examine the security failures that enabled the assassination attempt.

Al Weaver contributed.