LEWISTON, Maine (AP) — Children returned to school Tuesday and planned to go trick-or-treating in the evening after spending days locked in their homes following the deadliest mass shooting in Maine's history.

At Lewiston High School, hundreds of students returned to a facility which days earlier was transformed into a law enforcement command post with three helicopters utilizing the athletic fields and 300 vehicles filling the parking lot.

Inside, students were petting three therapy dogs, and were signing a large banner that said “Lewiston Strong,” the community’s new motto.

Calista Karas, a 16-year-old senior, said students have a lot to process. She said she was frightened sheltering at home and unable to immediately reach her mother, who was at work, when the shootings happened.

“You know, I just couldn’t believe something like this would happen here, to us,” Karas said. “And I know that sounds like detached, kind of like, ‘Oh, we wouldn’t be affected.’ But you never think it’s gonna happen to you when it happens, you know?”

Robert Card, a U.S. Army reservist from Bowdoin, fatally shot 18 people at a bowling alley and a bar in Lewiston on Wednesday night, authorities said. A massive search for the 40-year-old swept through the area until he was found dead Friday.

Police and other authorities had issued a shelter-in-place order for residents during the massive search for Card on land and water.

As students returned to school on Tuesday, Karas said she felt her stomach drop a bit when she walked through the school doors.

“Not because I felt unsafe,” she said. "But because I felt like, what’s going to happen from here on out? I was really unsure and uncertain of what was going to happen and how people would react. It was a weird experience to walk though school and see… life going on.”

Superintendent Jake Langlais said staff and students will take it one day at a time, understanding that some will need more support than others, depending on their proximity to deadly rampage.

“You know, having helicopters with search lights and infrared sensors over your homes and apartments is pretty uncomfortable. So we’re recognizing that everybody had some level of impact,” he said.