The FBI identified 20-year-old Thomas Matthew Crooks of Bethel Park, Pennsylvania as the suspect in the attempted assassination of former US President Donald Trump at a campaign rally.

The suspect was shot and killed by the Secret Service seconds after he allegedly fired shots toward a stage where Trump was speaking on Saturday in Butler, Pennsylvania.

The FBI said it was working to determine a motive for the attack. 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 in which Trump is challenging President Joe Biden would have been the first time Crooks had been old enough to vote in a presidential race.

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.

In Bethel Park, about an hour away from where the shooting occurred, the streets surrounding the Crooks’s home were blocked off by law enforcement authorities.

Mary and Stanley Priselac were standing on the porch of their nearby brick ranch-style home, trying to process the events of the last day and the spotlight now on their typically quiet residential neighborhood.

“Nothing happens on the street, everybody kind of minds their own business,” said Stanley Priselac, 72. “Everybody is kind of shocked, surprised, some dismay.”

“There’s never been a gun issue. There’s never been the police being called,” said Mary Priselac, 67. “You kind of have to wonder what didn’t he get in life? What led to this extreme?”

Thomas Crooks graduated in 2022 from Bethel Park High School, according to a statement from the Bethel Park School District received by local ABC affiliate WJET-TV.

“Our school district will cooperate fully with the active law enforcement investigation surrounding this case, and as such, we are limited in what we can publicly disclose,” the statement read.

The school district did not immediately respond to an inquiry from Reuters.

Crooks received a $500 “star award” from the National Math and Science Initiative, according to the Pittsburgh Tribune-Review 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.

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.