One person was killed and three other people were shot Thursday afternoon when a gunman with a shotgun entered a building on the campus of Seattle Pacific University and opened fire, police said.

When the gunman began reloading, a student who is a building monitor subdued the shooter with pepper spray, according to Capt. Chris Fowler of the Seattle Police Department. Other students then joined the monitor and held the shooter down, he said.

“They were able to pin the shooter to the ground until police arrived,” Fowler said during a news conference. The gunman was taken into custody a short time after.

The victims were taken to the hospital with gunshot wounds that ranged “from minor to life threatening,” the Seattle Fire Department said.

Aaron R. Ybarra, 26, was booked into the King County Jail late Thursday for investigation of murder, police said. Assistant Police Chief Paul McDonagh said at a news conference that the suspect was not a student at the school.

One of the victims, a 20-year-old man, was pronounced dead at Harborview Medical Center, according to police. Another victim, a woman, has life-threatening injuries. The other two victims, a man and a woman, are both in stable condition.

“This is a tragic moment for Seattle and a tragic moment for America once again,” Seattle Mayor Ed Murray (D) said in a news conference.

This shooting occurred shortly before 3:30 p.m. in Otto Miller Hall, a science and engineering building on the campus of Seattle Pacific.

The small Christian school, located about 10 minutes away from downtown Seattle, remained locked down for about 90 minutes after the shooting.

Police declared Otto Miller Hall secure at around 5 p.m. and the lockdown ended shortly after that. All evening classes were canceled.

Police officers conduct body searches on students after the shooting. (Dean Rutz/Seattle Times via AP)

Daniel J. Martin, the university president, held an emotional news conference on the school’s campus on Thursday evening.

His voice breaking, Martin described the feeling of “heartbreak” when he was first told of the shooting. He said the school would be offering grief counseling and holding a prayer service on the campus.

“It’s an opportunity for us to come together as a community and support those who have been affected,” Martin said.

Seattle Pacific University, founded in 1891, has more than 4,200 students.

(Google Maps)

There was initially some uncertainty from law enforcement officials regarding how many people were injured in the shooting and the number of suspects.

Seattle police had said there was conflicting information, which resulted in confusion over the number of victims. In addition, authorities had said after a gunman was taken into custody that they were looking for an additional suspect, but they said shortly after 4 p.m. that no other suspects were being sought.

This post will be updated. First published: 6:58 p.m.