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.
Demolition Ranch doesn’t really mention their politics. And there are plenty of Democrats that like guns.