(CNN) — When Briana Clarke heard popping sounds on a Seattle college campus, she thought the source must be something innocent — bursting balloons. Then she saw a classmate running frantically, saying someone had been shot.
A gunman had opened fire Thursday at Seattle Pacific University, killing one person and wounding two more before he was tackled by a student security guard, Seattle police said.
The gunman was reloading a shotgun when the tackler, working as a building monitor, used pepper spray and knocked him down, police Capt. Chris Fowler told reporters.
“Once on the ground, other students jumped on top of them and subdued the shooter,” he said.
The suspect, 26-year-old Aaron Ybarra, is not a student at the school, police said.
They say they think he acted alone, but the investigation is continuing. Police did not disclose a motive.
Ybarra is scheduled to make an initial court appearance at 2:30 p.m. (5:30 p.m. ET).
CNN affiliate KOMO identified the student security guard who tackled him as Jon Meis.
Meis carries pepper spray as a precautionary measure, his roommate Ryan Salgado told the The Seattle Times. The report described Meis as a devout Christian and dedicated student.
Could have been worse
At Otto Miller Hall, the building where the shots were fired, Clarke saw students covered in blood.
“When I walked outside and saw someone down, that was disturbing seeing a bunch of bullets around,” she said. “Seeing my friend outside being treated, that was hard to swallow.”
She thought that she could have been a victim.
Police are convinced the shooter would have harmed more people had those around him not intervened.
“This story is not about an evil act but about the people that actually lived through this scenario and assisted each other when things were pretty tragic,” said Seattle police Assistant Chief Paul McDonagh.
The suspect was armed with a shotgun, a knife and more ammunition, he said.
A man who said he was acquainted with Ybarra said he was surprised by the news, CNN affiliate KIRO reported.
“It just makes me ill,” he told the station. “I didn’t think that he was capable of something like that.”
The shooting began in the foyer of the building, which houses the university’s science, math and engineering departments, when the gunman confronted three people and shot them, Fowler said.
A 19-year-old man was declared dead at Harborview Medical Center.
A 20-year-old woman remained in critical but stable condition Friday after five hours of surgery, hospital spokeswoman Susan Gregg said. A 24-year-old man who police said suffered pellet wounds to the neck and chest was in satisfactory condition Friday, Gregg said said.
A fourth person was treated for minor injuries.
Officials immediately locked down the campus.
Blood on floor and walls
University President Daniel J. Martin told CNN affiliate KCPQ he turned on a monitor to view security camera images from Otto Miller Hall after he was alerted to the shooting.
“The students acted without regard for their own safety,” he said, his voice breaking with emotion.
Jillian Smith was taking a math test when she learned the campus was on lockdown. She said she kept taking the test until she heard police officers yelling.
“After we found out by social media what was going on, people were crying and everything,” Smith told CNN affiliate KOMO.
Police escorted students out of the building, where she saw blood on the floor and walls in the foyer.
Blake Oliveria was in a class when he heard the gunshots.
He said he removed his shoes in case he had to run but stayed in the classroom until police arrived to escort students out.
“I saw blood … on the ground,” he told CNN. “There were two or three big (pools) and some small ones scattered throughout the hallway.”
Mary Jones’ daughter attends Seattle Pacific but was unharmed. Still, she wonders how safe colleges will be without laws regulating access to guns.
“Where are the controls to keep our children from purchasing a handgun or any other kind of weapon? And does that take government controls to keep that from happening? I don’t know,” she told KOMO. “There has to be a greater understanding of what that weapon can do and the pain it can inflict on another person’s life.”
Seattle Pacific, a Christian university with a student population of more than 4,200, canceled classes Friday and scheduled a prayer service for noon (3 p.m. ET).