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.

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 man who opened fire at the U.S. Centers for Disease Control and Prevention headquarters last week, killing a police officer, died by suicide.