Crooks, from Bethel Park, Pa., fired shots at an outdoor rally in Butler, near Pittsburgh, with one bullet grazing Trump in the ear.
Sources stated that Crooks was positioned on the roof of a manufacturing plant over 130 yards from the stage at Butler Farm Show grounds.
He was fatally shot by Secret Service snipers, and an AR-style rifle was later recovered.
Bethel Park is located 40 miles south of where the Butler rally took place.
State voter records indicate that Crooks was a registered Republican.
The Intercept reported that Crooks made a $15 donation to the liberal ActBlue political action committee on January 20, 2021, the day of Joe Biden’s inauguration.
At the time of the donation, Crooks was 17 years old. He registered to vote as a Republican upon turning 18 in September of that same year, according to records.
The motive behind Crooks' attack on the presumptive Republican presidential nominee remains unclear.
Early Sunday, the FBI confirmed the Post’s report, identifying Crooks as the "subject involved" in the attack on Trump.