The suspect was shot and killed by the Secret Service seconds after he allegedly fired shots toward a stage where Trump was speaking in Butler, Pennsylvania.
The FBI said it was working to determine a motive for the attack, in which one rally attendee died and two other spectators were critically injured. Trump was shot in the ear.
State voter records show that Crooks was a registered Republican. The upcoming Nov. 5 election would have been the first time Crooks had been old enough to vote in a presidential race.
Crooks lived about an hour away from where the shooting took place in Butler. The Federal Aviation Administration said on Sunday that it closed the airspace over Bethel Park for "special security reasons."
When Crooks was 17 he made a $15 donation to ActBlue, a political action committee that raises money for left-leaning and Democratic politicians, according to a 2021 Federal Election Commission filing. The donation was earmarked for the Progressive Turnout Project, a national group that rallies Democrats to vote. The groups did not immediately respond to a Reuters request for comment.
Crooks' father, Matthew Crooks, 53, told CNN that he was trying to figure out what happened and would wait until he spoke to law enforcement before speaking about his son.
Thomas Crooks graduated in 2022 from Bethel Park High School, according to the Pittsburgh Tribune-Review. He received a $500 "star award" from the National Math and Science Initiative, according to the newspaper.
A 2022 graduation ceremony video cited by the New York Times shows Crooks receiving his high school diploma to some applause. Video from that ceremony posted online shows Crooks with glasses in a black graduation gown and posing with a school official. Reuters could not immediately verify the authenticity of the video.
Law enforcement officials said on Saturday that Crooks carried no identification to the site of the shooting and had to be identified using other methods.
"We're looking at photographs right now and we're trying to run his DNA and get biometric confirmation," Kevin Rojek, FBI special agent in charge, said during a press briefing.
USA Today reported that dozens of law enforcement vehicles were stationed outside a residence listed at the address on Crooks' voter registration record. Agents from the Bureau of Alcohol, Tobacco, Firearms and Explosives were on the scene and a bomb squad was at the residence, USA Today reported.
The perimeter of the residence of the suspect was guarded on Sunday by yellow police caution tape. An Allegheny County Police vehicle was parked outside.
“It’s insanity that anyone would do this,” Dan Maloney, a 30-year-old resident from the area was quoted as saying by USA Today.
Reuters could not immediately identify social media accounts or other online postings by Crooks. Meta, the parent company of Facebook and Instagram, did not immediately respond to questions on whether the platforms had removed any accounts related to the suspect.
