The FBI identified the shooter, who is dead, as Thomas Matthew Crooks of Bethel Park, Pennsylvania. A motive was not clear.
…
Bethel Park is a predominantly white, relatively well-to-do city in the southern reaches of greater Pittsburgh. The site of the rally, Butler, is about an hour’s drive north of Pittsburgh.
Pennsylvania voter records listed a Thomas Matthew Crooks with the same address and birth date as a registered Republican, though it was not clear from the records when that was put in place.
I read the FEC page. Same name, same zip code. Highly unlikely it’s someone else. Kid was 17 at the time and his job was “Not Employed”
NYTimes screenshot of the FEC document:
https://static01.nyt.com/newsgraphics/documenttools/fe91e6ba36695009/ac182c3a-full.pdf
The donation is almost certainly him