The gunman who opened fire Friday at the US Centers for Disease Control and Prevention broke into his father’s safe to get the five firearms recovered at the scene, state investigators said Tuesday, as some CDC workers seeking answers and reassurance from leadership were left dissatisfied by a short agency-wide meeting about the shooting.

The Georgia Bureau of Investigation said on Tuesday that the Georgia man who opened fire at the U.S. Centers for Disease Control and Prevention headquarters died by suicide in the incident last week.

A lone gunman fired 500 shots at the Centers for Disease Control and Prevention (CDC) headquarters in Friday’s deadly shooting, officials revealed Tuesday. Georgia Bureau of Investigation officials said six CDC buildings were struck in the attack.