WINDER, Ga. (AP) — Apalachee High School is set to reopen for classes Tuesday, almost three weeks after a school shooting killed two students and two teachers and injured nine others at the campus northeast of Atlanta.

Police say 14-year-old student Colt Gray slipped out of math class on the morning of Sept. 4 with an AR-15-style rifle given to him by his father. Within minutes, sounds of gunshots rippled across the hall and students crouched behind desks as teachers barricaded classroom doors. The school went into lockdown. Some students saw dead bodies as police officers led them to the football field, where others bled from the grazing of a bullet.

Now, Apalachee students are returning to school.

“I don’t want to go back because it is my last year and things are a little hard on me,” said Apalachee student Junior Garcia Ramirez, who was close to the football coach killed by the shooter.

But the open house hosted by the school on Monday helped Ramirez feel more “prepared” to go back. He said there “wasn’t a corner” of the school without staff, police officers, counselors or therapy dogs roaming the halls. He was especially glad to hear from school board officials and see how much they cared.

The atmosphere was one of both joy and unease, Ramirez said. Students were excited to be back together, but some were on edge about returning to classes as the blocked-off hallway where the shooting happened reminded them of when their safety was at risk.

Within two days of the shooting, Gray was charged with four counts of murder, and his father with related charges. Officials say Gray shot and killed Christian Angulo and Mason Schermerhorn, both 14, and teachers Richard Aspinwall, the 39-year-old football coach, and Cristina Irimie, 53. Another teacher and eight other students were injured.

Classes will resume for half days until students return from fall break in mid-October in what the school calls a “phased return.” The hall where the shooting occurred will be closed for the rest of the school year, so buses will take students to a building a few miles away for social studies classes. There will also be more law enforcement on campus in addition to counselors and therapy dogs, just like there were at the open house.

Apalachee parent Amanda Buckingham appreciates the shorter class periods with less school work.

“I think that’s going to help with the healing process and kids working together again with one another, and talking about their feelings while they’re in that setting,” Buckingham said.

Anxious parents brought their kids back to the neighboring elementary and middle schools in Winder less than a week after the shooting. Some expressed concerns about ongoing safety protocols at all three campuses, even as police officers stood outside.

Other community members worry the school isn’t doing enough, and petitioned for metal detectors, long-term plans for law enforcement, and at least temporary options for online learning.

“There are safety measures in place, and just because you don’t see them doesn’t mean they’re not there, contrary to what you hear and see on the social media world,” Barrow County Sheriff Jud Smith said at a press conference Monday in front of the school.

Kramon covers government and politics from Atlanta. She is a Report for America corps member.