The man who tried to assassinate Donald Trump appears to have posted anti-Semitic and anti-immigrant content online as a teenager, a senior FBI official said today, testifying at a Senate hearing.

FBI Deputy Director Paul Abati revealed the existence of this account on a social networking site, dating back to 2019-20. At the time, Thomas Crooks, the young man who opened fire at a Trump campaign rally, would have been 15 or 16 years old. This information is some of the first public information about the possible motive of the attacker.

“Something that was discovered very recently that I want to share is an account on a social networking site that is believed to be linked to the perpetrator and dates back to 2019-20,” Abati told senators. More than 700 comments were posted on this account. “Some of these comments, if ultimately attributed to the perpetrator, appear to express anti-Semitic and anti-immigrant themes and embrace political violence and are described as extreme,” he added.

Crooks shot him Trump with an AR-15 rifle on July 13, at a rally in Butler, Pennsylvania, injuring him in the ear. One supporter of the Republican candidate was killed and two others were injured in the shooting. Secret Service snipers killed Crooks a short time later.

Police describe Crooks as a lonely youth with no close friends and a social network limited to only his immediate family members.

The assassination attempt on Trump led to the resignation of its director Secret Service Kimberly Cheatle, which was under pressure from both parties. Her successor, the Ronald Rowe acting director, said today that he went to Butler and climbed onto the roof of another building near the one from which Crooks fired. “What I saw makes me ashamed,” he told a joint meeting of the Homeland Security and Judiciary Committees. “After 25 years in the Secret Service, I cannot justify why that roof was not guarded,” he added, assuring that steps have now been taken to avoid similar errors in the future.

According to Rowe, before launching his attack Crooks flew a small, remote-controlled plane near the gathering area. However, authorities did not locate it because the drone’s tracking system was not working properly.