Three young children and three staff members were shot in Nashville private Christian elementary, the Covenant School, after 28-year-old Audrey Hale shot up the building. Hale was shot 14 minutes later by the police.

Hale was being treated for an emotional disorder, posting about his “suffering in social media posts over the past year,” according to one of his former teachers. And while evidence of Hale resenting the school has not been verified, police discovered detailed maps of the school he drew and text messages between he and his friend in which Hale sent “I’m planning to die today. You’ll probably hear about me on the news.”

“Nashville comes together like no other place to comfort those who have suffered an unspeakable loss,” Nashville Police Chief John Drake said at the citywide vigil held two days after the shooting to honor the students and staff members killed. “We also comfort each other as we try to emotionally cope with this horrific crime that occurred Monday.”

Katherine Koonce, head of the school and one of the victims, left her office after she heard gunshots and spent her last moments protecting children “in her care.” Various other adults in the school called 911 after hearing gunshots, and teachers followed practiced procedures; they hid students in their classrooms and secured the doors, preventing more children from being killed. Councilman Russ Pulley said the head of the school and one of the victims, Katherine Koonce, left her office after she heard gunshots and spent her last moments protecting children “in her care.”

“Just two days ago was our worst day,” Mayor John Cooper said at the vigil. “Our heart is broken. Our city united as we mourn together.”

146 Tennesseans have been killed because of gun violence since January, and the most recent at the Covenant School stimulated protests for gun control and gun violence in schools. Lawmakers have recently been discussing such topics.