AP PHOTO Police respond to Perry High School in Perry on Thursday.

PERRY — A 17-year-old opened fire at a small-town Iowa high school before classes resumed on the first day after the winter break, killing a sixth-grader and wounding five others Thursday as students barricaded in offices, ducked into classrooms and fled in panic.

The suspect, a student at the school in Perry, died of what investigators believe is a self-inflicted gunshot wound, an Iowa Division of Criminal Investigation official said. Authorities said one of the five people wounded was an administrator, later identified by his alma mater as Perry High School Principal Dan Marburger.

Authorities identified the shooter as Dylan Butler, 17, and provided no information about a possible motive. Two friends and their mother who spoke with The Associated Press said Butler was a quiet person who had been bullied for years.

Perry has about 8,000 residents and is about 40 miles (65 kilometers) northwest of Des Moines, on the edge of the state capital’s metropolitan area. It is home to a large pork-processing plant, and low-slung, single-story homes spread among trees now shorn of their leaves by winter. The high school and middle school are connected, sitting on the east edge of town.

Authorities said Butler had a pump-action shotgun and a small-caliber handgun. Mitch Mortvedt, the state investigation division’s assistant director, said during a news conference that authorities also found a “pretty rudimentary” improvised explosive device and rendered it safe.

The suspect’s motive is being investigated and authorities are looking into “a number of social media posts” he made around the time of the shooting, Mortvedt added.

A law enforcement official briefed on the investigation said federal and state investigators are interviewing Butler’s friends and analyzing Butler’s social media profiles, including posts on TikTok and Reddit, as they work to identify a motive.

Shortly before Thursday’s shooting, Butler posted a photo on TikTok inside the bathroom of Perry High School, the official said. The photo was captioned “now we wait” and the song “Stray Bullet” by the German band KMFDM accompanied it. Investigators have also found other photos Butler posted posing with firearms, according to the official, who was not authorized to publicly discuss details of the investigation and spoke to AP on condition of anonymity.

Sisters Yesenia Roeder and Khamya Hall, both 17, said alongside their mother, Alita, that Butler was bullied relentlessly since elementary school, but it escalated recently when his younger sister started getting picked on, too. Officials at the school didn’t intervene, they said, and that was “the last straw” for Butler.

“He was hurting. He got tired. He got tired of the bullying. He got tired of the harassment,” Yesenia Roeder Hall, 17, said. “Was it a smart idea to shoot up the school? No. God, no.”

Perry High School senior Ava Augustus said she was awaiting a counselor in a school office when she heard three shots. Unable to flee through a small window, she and others barricaded the door and were ready to throw things if necessary.

“And then we hear ‘He’s down. You can go out,'” Augustus said through tears. “And I run and you can just see glass everywhere, blood on the floor. I get to my car and they’re taking a girl out of the auditorium who had been shot in her leg.”

Three gunshot victims were being treated at Iowa Methodist Medical Center in Des Moines, a spokesperson said. Others were taken to a second Des Moines hospital, a spokesperson for MercyOne Des Moines Medical Center confirmed.

Mortvedt said one person was in critical condition but the injuries didn’t appear to be life-threatening. The other victims were stable, he said.

Hundreds of community members gathered for a candlelight prayer vigil Thursday evening at a park where hours earlier, students had been dropped off to reunite with their families after the shooting. Bundled up against freezing temperatures, they listened to pastors from many faiths and heard a message of hope in both English and Spanish.

A post on the high school’s Facebook page said it would be closed Friday and counseling services would be available for students, faculty and others in the community.

Gov. Kim Reynolds said: “This senseless tragedy has shaken our entire state to its core.”

In Washington, President Joe Biden and U.S. Attorney General Merrick Garland were briefed on the shooting.

The shooting occurred ahead of Iowa’s Jan. 15 first-in-the-nation presidential caucuses. GOP candidate Vivek Ramaswamy had a 9 a.m. campaign event scheduled in Perry about 1 1/2 miles (2.4 kilometers) from the school but canceled it to hold a prayer and intimate discussion with area residents.

Mass shootings across the U.S. have long brought calls for stricter gun laws from gun safety advocates, and Thursday’s did within hours. But that idea has been a non-starter for many Republicans, particularly in rural, GOP-leaning states like Iowa.

As of July 2021, Iowa does not require a permit to purchase a handgun or carry a firearm in public, though it mandates a background check for anyone buying a handgun without a permit.

Ramaswamy said the shooting is a sign of a “psychological sickness” in the country. In Des Moines, GOP rival and Florida Gov. Ron DeSantis said gun violence “is more of a local and state issue” in an interview with the Des Moines Register and NBC News.

The high school is part of the 1,785-student Perry Community School District. Perry is more diverse than Iowa as a whole. Census figures show 31% of its residents are Hispanic, compared to less than 7% statewide. Those figures also show nearly 19% of the town’s residents were born outside the U.S.

Authorities said an active shooter was reported at 7:37 a.m. Thursday and officers arrived within minutes. Emergency vehicles surrounded the complex.

“Officers immediately attempted to locate the source of the threat and quickly found what appeared to be the shooter with a self-inflicted gunshot wound,” Mortvedt said.

Rachael Kares, an 18-year-old senior, was wrapping up jazz band practice when she and her bandmates heard four gunshots, spaced apart.

“We all just jumped,” Kares said. “My band teacher looked at us and yelled, ‘Run!’ So we ran.”

Kares and many others ran out past the football field, as people yelled, “Get out! Get out!” She said she heard additional shots as she ran, but didn’t know how many. She was more concerned about getting home to her 3-year-old son.

Zander Shelley, 15, was in a hallway when he heard gunshots and dashed into a classroom, according to his father, Kevin Shelley. Zander was grazed twice and hid in the classroom before texting his father at 7:36 a.m.

Kevin Shelley, who drives a garbage truck, told his boss he had to run. “It was the most scared I’ve been in my entire life,” he said.

He later posted a photo on Facebook of his son being treated at the Methodist Medical Center and said the boy was feeling fine.

He added: “I am still shaking and tho I dont show it I’m not ok.”