Sen. Rick Scott, R-Fla., wrote a letter to President Joe Biden on Thursday demanding "absolute transparency and accountability" from his administration with the investigation into the rally shooting.

While Scott noted that he's pleased to see Congressional investigations moving forward, he said more accountability is needed.

Scott called on FBI Director Christopher Wray, Secret Service Director Kimberly Cheatle and Department of Homeland Security Secretary Alejandro Mayorkas to hold a "daily public press conference to share updates and answer questions from the American people."

Scott asked Biden if any disciplinary action will be taken against Wray, Cheatle or Mayorkas.

"Has anyone employed by the U.S. government had disciplinary action taken against them, including being placed on leave, for action or inaction connected to the assassination attempt, murder and severe injuries that occurred on July 13th?" Scott wrote.

Scott also wrote a list of 18 questions to Cheatle, which included: "If the buck stops with you, and this has clearly been established as a colossal USSS breakdown and national embarrassment of historic proportion, why haven't you resigned?"

-ABC News’ Allison Pecorin

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."