The Georgia Bureau of Investigation identified the gunman as 30-year-old Patrick Joseph White, of Kennesaw, Georgia.

CDC security guards stopped White from driving into the campus on Friday before he parked near a pharmacy across the street and opened fire from a sidewalk. The bullets pierced “blast-resistant” windows across the campus, pinning employees down during the barrage. More than 500 shell casings were recovered, the GBI said.

The Georgia Bureau of Investigation has identified the man who opened fire at the U.S. Centers for Disease Control and Prevention as 30-year-old Patrick Joseph White of Kennesaw,