Acting Secret Service Director Ronald Rowe on Tuesday acknowledged that the attempted assassination of Donald Trump on July 13 represented a failure on multiple levels, and pledged his full support to the various ongoing investigations into the events of that day.

In opening comments to the Senate committees on homeland security and the judiciary, Rowe said he traveled to Butler, Pennsylvania, earlier this month to see the agencys failures firsthand.

What I saw made me ashamed, he said. 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.

FBI Deputy Director Paul Abbate also answered questions at Tuesdays hearing, telling senators the agency has discovered a trove of extremist content that appears to have been written by the would-be assassin Thomas Matthew Crooks .

Abbate said a social media account that Crooks appears to have used in 2019 and 2020 had over 700 comments that appear to reflect antisemitic and anti-immigration themes, to espouse political violence, and are described as extreme in nature. No clear motive has been identified, however.

The agency is investigating the shooting as both an attempted assassination and an incident of domestic terrorism. Sen. Ron Johnson (R-Wis.) objected to the second label, telling Abbate he feared that categorizing the shooting as terrorism would make the investigation potentially partisan.