(NewsNation) — The 27th Director of the U.S. Secret Service, Kimberly Cheatle, resigned from her post Tuesday in the wake of the assassination attempt against former President Donald Trump.

Cheatle, who was sworn into office on Sept. 17, 2022, during President Joe Biden’s administration, faced countless calls to resign after taking responsibility for the security lapse that led to Trump getting shot in the head.

The shooter, identified as 20-year-old Thomas Matthew Crooks, was killed by Secret Service agents just seconds into the attempted assassination.

On Monday, Cheatle testified publicly in front of the House Oversight Committee after a week of closed-door interviews. Admitting that the agency “failed,” Cheatle told lawmakers that she takes full responsibility for any security lapse on the day of the attack.

“As an agency, we are fully cooperating with the FBI’s investigation, the oversight you have initiated here, and conducting our own internal mission assurance review at my direction,” she said. “We must learn what happened, and I will move heaven and earth to ensure an incident like July 13th does not happen again. Thinking about what we should have done differently is never far from my thoughts.”

Who is Secret Service Director Kimberly Cheatle?

The second woman to have led the Secret Service, Cheatle spent nearly three decades in the Secret Service in various roles before her appointment.

Prior to rejoining the agency in 2022, Cheatle served as senior director in global security at PepsiCo, where she “was responsible for directing and implementing security protocols for the company’s facilities in North America,” according to her Secret Service biography.

What to know about Secret Service Director Kimberly Cheatle

One of Cheatle’s former Secret Service positions included working on the Vice Presidential Protective Division when Biden was former President Barack Obama’s second in command.

Biden cited this relationship and her prior experience in an August 2022 statement announcing her leadership appointment.

“When Kim served on my security detail when I was Vice President, we came to trust her judgment and counsel. She is a distinguished law enforcement professional with exceptional leadership skills, and was easily the best choice to lead the agency at a critical moment for the Secret Service,” said Biden.

Cheatle took charge of the Secret Service in the aftermath of the Jan. 6, 2021, attack on the U.S. Capitol.

“She has my complete trust, and I look forward to working with her,” the statement read.

History of the Secret Service

The Secret Service is one of the nation’s oldest federal law enforcement agencies. First created in 1865 to address counterfeiting in America’s financial infancy, the agents now synonymous with the presidential office began as a bureau in the Treasury Department.

The agency’s role shifted as a result of an assassination, according to the Secret Service’s official website.

“After the assassination of President McKinley in 1901, the Secret Service was tasked with the full-time protection of the President of the United States,” it reads. “Over time, this protective mission has been expanded by statutory changes, Presidential Decision Directives, Homeland Security Presidential Directives, National Security Presidential Directives, and various Executive Orders.”

In 1998, the agency once again expanded due to Presidential Decision Directive 62 (PDD 62), which “established the Secret Service as the lead federal agency for coordinating the development and implementation of security plans for National Special Security Events (NSSEs).”

NSSEs include:

• Major political party conventions
• Inaugurations
• Summits with other world leaders
• U.N. assemblies
• Major sporting events, abroad and domestic
• State of the Union addresses
• State funerals
• Other “events of national significance”

Trump’s assassination attempt

The shooting on July 13 was the most serious attempt to assassinate a president or presidential candidate since Ronald Reagan was shot in 1981.

Law enforcement officials tell the Associated Press that bomb-making materials were found inside a vehicle linked to the suspect in the Trump rally shooting. There were also bomb-making materials found at his home. The two officials were not authorized to speak publicly and spoke to the AP on condition of anonymity.

Witnesses told NewsNation affiliates about their experiences, with multiple people claiming they saw Crooks climbing up to the roof of a building outside of the rally’s perimeter. Police were allegedly alerted about the armed man, but it’s unclear how law enforcement and the Secret Service interacted with each other during the event.

NewsNation’s Damita Menezes, Sean Noone and the Associated Press contributed to this report.