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

Investigators released a photo on Tuesday of the gunman, Patrick White, of Kennesaw. Channel 2 Cobb County Bureau Chief Michele Newell has been digging into White’s past, where she learned his father had called police about White’s mental health. GBI director Chris Hosey said White took his father’s guns for the attack.

A search of Patrick Joseph White’s home revealed documents in which he indicated his discontent with the vaccine, they said.