House Judiciary Committee Chairman Jim Jordan, R-Ohio, wrote a letter to FBI Director Christopher Wray requesting more information on the Trump rally shooting -- a preview of what GOP members on the committee may ask Wray when he appears at a hearing on Wednesday, July 24.

Jordan alleges that "whistleblowers have disclosed to the Committee that the U.S. Secret Service (USSS) did not have proper resources for President Trump's campaign event in Butler, Pennsylvania because of staffing shortages due to the North Atlantic Treaty Organization (NATO) summit and First Lady Jill Biden's event in Pittsburgh."

"The information provided to this Committee raises serious questions about the thoroughness of the security planning by local, state, and federal law enforcement agencies in support of President Trump's campaign rally," Jordan said. "Law enforcement overlooked a number of vulnerabilities prior to and during the event."

-ABC News’ Lauren Peller

The family of Corey Comperatore, the man killed at Saturday’s rally while shielding his family from the gunfire, is speaking out in a new statement.

"Corey Comperatore was our beloved father and husband, and a friend to so many throughout the Butler region," the family said. "He was a local leader and veteran, a former fire chief, and a committed Christian who found peace and joy through our church."

Comperatore, 50, leaves behind a wife and two daughters.

"We thank the countless people who have prayed for us throughout the past week," the family added.

As investigators continue to work to decipher a motive in the assassination attempt against former President Donald Trump, one expert said the 20-year-old gunman, Thomas Matthew Crooks, was likely motivated by a "combination of factors."

"What is beginning to emerge is a portrait of a troubled young person who turned to violence," said ABC News contributor John Cohen, the former head of intelligence at the Department of Homeland Security who specialized in the radicalization and the phenomenon of mass shooters.

"Investigators may never determine a single or precise motive for the attack. Likely, it was a combination of mental health issues, ideological beliefs and a sense of personal grievance -- the same combination of factors present in almost every school shooting and mass casualty attack over the past several years," Cohen said. "As with those incidents, the warning signs were there, they were just not recognized. The threat was real, but people around him did not understand what they were witnessing or how it would play out."

Sen. Marsha Blackburn, R-Tenn., and other Republican senators chased down Secret Service Director Kim Cheatle at the Republican National Convention Wednesday.

Multiple sources told ABC News that Cheatle was on the suite level of the convention hall, and when she was spotted, multiple senators chased her.

"This was an assassination attempt -- you owe the people answers, you owe President Trump answers," Blackburn said in reference to the shooting at Trump's rally on Saturday, according to a video.

Sen. John Barrasso, R-Wyoming, is heard accusing Cheatle of "stonewalling" them as she refused to respond to their repeated jeers, based on videos posted to the senators' social media.

Blackburn said Sen. James Lankford, R-Okla, and Sen. Kevin Cramer, R-N.D., also joined them in confronting the director.

"She can run, but she cannot hide," Blackburn said in a separate video. "Because the American people want to know how an assassination attempt was carried out on former President Donald Trump."

-ABC News’ Katherine Faulders and Allie Pecorin