Gunman Patrick Joseph White expressed discontent with the COVID-19 vaccinations in writings he made before the shooting, authorities said.

The suspect in the shooting targeting the Centers for Disease Control and Prevention had letters that showed his “discontent” with COVID-19 vaccines.

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.