Two Portland State University police officers have been placed on paid administrative leave after shooting and killing a man in the midst of a brawl outside a downtown bar at the edge of campus.

The university says it is cooperating with Portland police as they investigate the shooting, which has grown increasingly controversial as bystander videos of the moments leading up to the incident have been made public.

"Campus safety is our top priority at PSU," university president Rahmat Shoureshi said in a letter sent to the campus community. "As you know, we are an urban campus, and that presents challenges. We work hard to provide an environment at PSU that is safe and welcoming. We will continue to work with the Portland Police Bureau to communicate developments in the investigation and keep you informed."

Early Friday morning, a group of men started tussling in front of sports bar the Cheerful Tortoise. Bystander video shows a man with a gun holstered on his hip try to break up the fight. He tripped and the gun appears to be knocked loose.

Then officers shouted "Drop the gun," before firing at the man.

A witness told Oregon Public Broadcasting that the altercation started with a different man in a blue shirt who called another person a racial slur.

"The guy in blue had used some racial slurs earlier when they were in the street kiddy corner to where they were in this video and that's what brought it to this point, and started the whole thing," Keyaira Smith told the radio station.  The man in blue started a fight, and another man stepped in to try to break it up. Then, he tripped.

"The gun slipped out of the holster when he had fallen, and I think he may have tried to retrieve it," Smith said. "Then they said 'gun'… There was absolutely no hesitation at all. [The officer] went straight for his gun."

Smith told OPB that police shot the victim while his back was turned toward them.

Shoureshi says this is the first officer-involved shooting at PSU and the university will assess its internal policies and procedures.

"Some of the questions we have been asked are about the conflicting reports from media outlets interviewing those who say they witnessed the incident," the university president said. "Portland Police investigators are interviewing witnesses, and those interviews are ongoing. Investigators have asked any witnesses with video of the incident to contact them. At this time, our focus is on fact gathering rather than speculation."

UPDATE: PSU identified the officers involved in the shooting. Shawn McKenzie and James Dewey have been sworn officers with the PSU police since 2016.