Aaron Ybarra, a 26-year-old gunman, has been taken into custody late Thursday, after a shooting at Seattle Pacific University left one person dead and three others injured.

A man in his 20s, who sustained critical injuries in the shooting, was pronounced dead at Harborview Medical Center about 90 minutes after the 3:30 p.m. shooting at the evangelical Christian school.

The hospital officials said that a 20-year-old woman underwent surgery and two other men, aged 24 and 22 respectively, are out of danger.

Police officials said that the shooter, who is not a student of the Christian University in Seattle University, opened fire with a shotgun inside the lobby of Otto Miller Hall on the campus. The building houses the university's science, math and engineering departments.

Seattle Police Capt. Chris Fowler said that when the gunman paused to reload, a student guard pepper-sprayed him and knocked him down. Once on the ground, other students held on to the shooter until the police arrived.

"The shooter began to reload his shotgun and a student that is the building monitor inside the hall confronted the shooter, was able to subdued the individual, and once on the ground, other students jumped on top of him and were able to pin the shooter to the ground until police arrived," said Fowler, USA Today reports.

Police authorities will not be releasing the details of the suspect until formal charges are pressed against him. They haven't yet determined the motive of the shooting but believe that the gunman acted alone.

The suspect from Seattle "was obsessed'' with the 1999 Columbine High School shootings and even visited the Colorado school where two students killed 15 people and injured 21 others, KIRO-TV reports.

Seattle police Asst. Chief Paul McDonagh said that the shooter was armed with a shotgun, a knife and additional rounds of ammunition, CNN reports.

"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," McDonagh said.

Students and campus community members took to different social media platforms to express their gratitude to John Meis, the engineering student who pepper-sprayed and restrained the gunman.

"I'm proud of the selfless actions that my roommate, Jon Meis, showed today taking down the shooter. He is a hero," Matt Garcia tweeted.