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.

Documents found in a search of the suspect’s home “expressed the shooter’s discontent with the COVID-19 vaccinations,” Georgia Bureau of Investigation Director Chris Hosey said.

The Georgia man accused of firing more than 500 shots at the CDC headquarters aimed to publicize his opposition to COVID-19 vaccines, authorities said Tuesday.