The FBI early Sunday named Thomas Matthew Crooks, 20, of Bethel Park, Pennsylvania, as the subject involved in the assassination attempt on former President Donald Trump.

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The agency said the investigation remains active and ongoing.

The political leanings of Crooks were not immediately clear. Records show Crooks was registered as a Republican voter in Pennsylvania, but federal campaign finance reports also show he gave $15 to a progressive political action committee on Jan. 20, 2021, the day President Joe Biden was sworn in to office.

Attendee Dead, Two Critically Injured

One attendee was killed and two spectators were critically injured, authorities said. All were identified as men. The Secret Service killed the suspected shooter — who it said attacked from an elevated position outside the rally venue, a farm show in Butler, Pennsylvania — and said Trump was safe.

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The attack was the most serious attempt to assassinate a president or presidential candidate since Ronald Reagan was shot in 1981. It drew new attention to concerns about political violence in a deeply polarized U.S. less than four months before the presidential election. And it could alter the tenor and security posture at the Republican National Convention, which will begin Monday in Milwaukee.

Organizers said the convention would proceed as planned.