Police in Seattle have praised the bravery of a student after a man armed with a shotgun opened fire in a University building, killing one person and injuring three others.
The student confronted the man as he was reloading and subdued him with pepper spray.
Other students then managed to pin him to the ground until police arrived.
The Seattle Police Department said via Twitter that Aaron Ybarra, 26, had been booked into King County Jail for the shooting at Seattle Pacific University.
The lone suspect, who was not a student, entered an academic building of the university in the late afternoon and shot three people, police said.
He was disarmed as he paused to reload his gun and was pepper sprayed by a student security guard.
"Other students jumped on top of them, and they were able to pin the shooter to the ground until police arrived" minutes later, police Captain Chris Fowler told reporters on the scene.
Americans are engaged in a protracted debate over gun control regulations after a series of shootings in public places such as schools and theatres.
On 24 May, a 22-year-old gunman killed six people before taking his own life in a rampage across a California college town.
One eyewitness in Seattle, Chris Howard, a 22-year-old junior, told Reuters news agency he was in a classroom when one of the male victims rushed in bleeding from the neck and told students to lock the doors.
Stepping outside the classroom moments later, Mr Howard said he saw the gunman lying on the floor with the student security monitor on top of him, surrounded by bullet shells.
He said he saw a second victim with a tourniquet tied around a bleeding arm, being assisted by another student.
He was armed with a gun and a knife and extra ammunition, police said.
The suspect could face a murder charge, Mr Fowler told an evening news conference.
A representative of Harbor view Medical Center in Seattle aid four patients from the shooting were brought to the hospital and that one, a man in his 20s, had died.
Two other men, aged 22 and 24, were listed in satisfactory condition, and a 20-year-old woman was listed as critical and undergoing surgery, the hospital official said.
One of the men suffered pellet wounds to his neck and chest and the other suffered minor injuries, police said.