Update, 4:38 a.m. EDT: A student building monitor who overpowered the gunman by attacking him with pepper spray when he stopped to reload, and then disarmed him and held him down with the help of others on campus have been hailed as heroes, and credited with preventing more casualties in the shooting incident that claimed the lives of one student and injured three others.

"There are a number of heroes in this," Assistant Police Chief Paul McDonagh said at a press conference, ABC News reported. "The people around him (the gunman) stepped up."

Update, 2:39 a.m. EDT: Authorities have identified the shooter as 26-year-old Aaron Ybarra from Mountlake Terrace, a neighborhood about 12 miles north of Seattle Pacific University, The Seattle Times reported, adding that he was booked into the King County jail on murder charges. 

“He was hellbent on a killing a lot of people today,” a source in law enforcement who was briefed on the investigation, told the Times.

Update, 12:35 a.m. EDT: Three people were wounded and one person killed after a gunman opened fire at this Christian college in Seattle, Reuters reported, adding that the suspect -- a 24-year-old man who is not a student at the university -- had a gun, a knife and extra ammunition, citing authorities. 

Update, 9:40 p.m.:  Seattle police said that a student tackled the shooter who killed one person and wounded two others Thursday at Seattle Pacific University, CNN reported.

Police Capt. Chris Fowler told reporters that the gunman was reloading a shotgun when the student, a building monitor, used pepper spray and knocked him to the ground, according to the news site.

"Once on the ground, other students jumped on top of them and subdued the shooter," Fowler said. The suspect, whose identity was not immediately released, is in custody, police said, CNN added.

One eyewitness, student Chris Howard, 22, told Reuters that he saw the gunman lying on the floor of Otto Miller Hall after the suspect had been subdued with a student security guard lying on top of him, surrounded by bullet shells.

Howard said he also saw a gun and a knife on the floor near the suspect, Reuters added. Howard said that the gunman appeared to be in his mid-30s and didn't appear to be a student at the university.

John Lindberg, 53, a physics professor also on the scene said the ammunition he saw on the floor appeared to be from a shotgun, Reuters added.

Update, 8:30 p.m.: A spokeswoman for Harboview Medical Center said one man shot at Seattle Pacific University on Thursday has died. At least three other people were wounded, Reuters reported.

The man who died was described by the spokeswoman as someone in his 20s. She also said that a 20-year-old woman was in critical condition and undergoing surgery. Two other victims were in satisfactory condition.

Original story:

Seattle police are investigating a shooting at Otto Miller Hall on the Seattle Pacific University campus, the Seattle Times reported. Several people were shot, and one victim was rushed to Harborview Medical Center with life-threatening wounds, according to news reports.

One shooter was apprehended shortly after the shots were reported at 3:25 p.m. PST Thursday on the Queen Anne neighborhood campus, according to Seattlepi.com. Following reports of a second shooter, police were searching the scene, the news site said. The possible second gunman's connection to the shooting wasn't immediately clear. That suspect is described as a white male, wearing a long-sleeve blue shirt wth vertical stripes armed with handgun, the Seattle Times reported.

The campus has been placed on lockdown. Students are being advised to stay off campus, according to the school's website, the newspaper said. "Classes are suspended. Please do not come to campus," the university said in a post on its official Twitter account, according to CNN.

Seattle police said on social media that at least three people were shot, according to Reuters.

Seattle Pacific is a Christian university with a student population of 4,270, CNN reported.

This is a breaking news story.