An FBI investigation has found that the shooter who tried to kill former President Donald Trump last month held deep antisemitic beliefs.

During a U.S. Senate hearing on Tuesday, FBI Deputy Director Paul Abbate revealed the existence of a social media account believed to be associated with Thomas Crooks, the 20-year-old man responsible for the assassination attempt on Trump. The account dates back to 2019 when Crooks was 15 years old and contained over 700 comments with antisemitic and extremist content.

“Some of these comments, if ultimately attributable to the shooter, appear to reflect antisemitic and anti-immigration themes, espouse political violence, and are described as extreme in nature,” said Abbate.

During a campaign rally in Pennsylvania on July 13, Crooks opened fire with an AR-15-style rifle. President Trump suffered a wound to his ear, while one rally attendee was killed and two others were injured. Secret Service snipers quickly neutralized the 20-year-old.

Abbate also provided additional information about the events leading up to the attack. Crooks had flown a drone near the rally site prior to his assassination attempt. Due to problems with cellular network bandwidth, Crooks’ drone went undetected despite the system being specifically designed to identify such threats.

Marking the first shooting of a U.S. president or major party candidate in more than four decades, questions about campaign security have been raised. The fallout was swift, with Secret Service Director Kimberly Cheatle resigning under bipartisan congressional pressure.

Acting Secret Service Director Ronald Rowe, who succeeded Cheatle, provided a candid assessment of the security failures during a joint hearing of the Senate Homeland Security and Judiciary Committees.

“What I saw made me ashamed. As a career law enforcement officer, and a 25-year veteran with the Secret Service, I cannot defend why that roof was not better secured,” Rowe stated.

Rowe also confirmed that Secret Service counter-snipers and members of Trump’s security detail were unaware of Crooks’ presence on the nearby building’s roof.

Meanwhile, the Secret Service has since taken steps to prevent similar lapses. Six people have been added to the agency’s protection list, including Republican vice presidential candidate JD Vance and his family, as well as independent presidential candidate Robert F. Kennedy Jr.