Cole Tomas Allen, 31, of Torrance, California, will appear in court Monday, accused of attempting to assassinate President Trump at the White House Correspondents Dinner, law enforcement officials said.

Allen was charged with using a firearm during a crime of violence and assault on a federal officer, according to U.S. attorney for the District of Columbia Jeanine Pirro. He will be arraigned in Federal District Court. Further charges are expected. Trump was not injured in the attack.

It is not yet known what the motive was for the attack, in which Allen allegedly entered the Washington Hilton hotel, charged through security carrying a shotgun, a handgun and multiple knives, before shooting and hitting a member of the U.S. Secret Service detail assigned to protect Trump. The Secret Service member was wearing a bullet-proof vest, according to The New York Times, and survived the attack. (The Hilton is the same hotel where President Reagan was shot, in 1981.)

Allen got off five to eight shots before he was brought down by security personnel, the BBC reported.

Allen was immediately arrested, taken into custody, and evaluated in hospital on Saturday night, according to multiple reports. He was believed to have checked in as a guest at the hotel prior to the attack.

Washington interim police chief Jeffery Carroll told reporters, “At this point, it does appear he is a lone actor, a lone gunman.”

Details are beginning to emerge about Allen’s background, from his social media account, and his neighbours.

Allen was a tutor and amateur video game developer, according to the Associated Press. 

He obtained a bachelor’s degree in 2017 in mechanical engineering from the California Institute of Technology in Pasadena. As an undergrad, he created a model for a new emergency brake for wheelchairs, the AP said. He then a master’s degree in computer science from California State University-Dominguez Hills. 

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Allen created a game called “Bohrdom,” according to the New York Times, in 2018. In an online post, Allen described it as “a skill-based, non-violent asymmetrical fighting game loosely derived from a chemistry model that is itself loosely based on reality.” 

At CalTech, Allen was reportedly a member of the school’s student club for nerf gun fighters. The New York Times also said he was a member of the school’s Christian fellowship. 

Allen’s Linkedin profile also said he was on a team at CalTech that won a robotics competition in 2016, according to Reuters.

Allen’s Linkedin listed him as an employee for the previous six years at C2 Education, an exam and test prep services provider. At one point he was named the company’s “Teacher of the Month,” the AP said.

Allen was registered to vote but recorded no party preference.

The Times also said he donated $25 to ActBlue, a Democratic party political action committee that raises funds for Democrats, per Federal Election Commission records. The donation was listed for Kamala Harris’s presidential campaign. 

Trump posted a photo of Allen being arrested Saturday night:

Neighbors on Allen’s street in Torrance said they had seen no signs that Allen might have been dangerous. “We see them every day and we just say hi and they’re very nice,” one told the LA Times. “They’re peaceful people, they don’t make any noise and when they see you they say hi.”

Dylan Wakayama, who knew Allen because he tutored high school students who are members of the Asian American Civic Trust, told The Times his impression of Allen was that he was intelligent, quiet, and nice.

“I think all of us in Torrance would be shocked if this is the man who attempted to kill the president of the United States,” he said.