President Trump and other top officials were whisked away from the event while hundreds of attendees sheltered under their tables as gunfire rang out.
According to his social media and professional profiles, Allen is a teacher, engineer and videogame developer living in southern California. He legally obtained multiple guns before the attack took place, according to Bloomberg.
He is expected to face charges on Monday, including using a firearm during a crime of violence and assault on a federal officer with a dangerous weapon, according to U.S. Attorney for the District of Columbia Jeanine Pirro.
Here’s what we know about Allen.
A teacher from southern California
Allen lives in Torrance, California, a suburban city in the Los Angeles metropolitan area with a population of around 143,000. Torrance’s mayor, George Chen, released a statement on social media late Saturday night in response to the reports naming Allen, saying that “one individual’s alleged actions do not define our city.”