Riverside County fire investigators are trying to pin down the source of a 15-acre brushfire in Beaumont. The blaze at South Highland Springs and Breckenridge Avenues was reported at 5:25 p.m. Friday. About 30 firefighters, a helicopter, two air tankers and a small plane had the fire controlled by nine p.m. No structures were damaged. One firefighter was taken to a hospital to be checked out. The cause of the fire was listed as “shooting” on the Riverside County Fire Department’s Website, but it was unclear if whoever was shooting in the area would be cited in connection with the fire.