LAS VEGAS >> Images of a campus police officer diving behind a patrol vehicle to escape gunfire and then fatally shooting a gunman outside a building at the University of Nevada, Las Vegas, are among footage in newly released video of a deadly rampage that left three professors dead and a fourth badly wounded last December.

The deadly shootout captured by campus surveillance cameras ended what authorities say was 10 minutes of terror unleashed by a 67-year-old former business professor from North Carolina whose applications to teach at UNLV had been rejected.

The gunman, Anthony Polito, was armed with a legally purchased 9 mm handgun, carried nine bullet magazines, and had a target list of names, although none of the people shot was on that list, police said.

The university on Thursday released 20 hours of footage from campus security and officer body cameras, along with more than an hour of recordings of 911 calls made to campus police.

Sounds of the gunfire that killed three people in upper floors of the five-story business school sent people fleeing from the nearby Student Union just before noon on a sunny day. Video shows a campus police officer, running across the plaza toward the business school building, arrived within 78 seconds of the shooting.

“It is difficult to listen to these recordings and watch the videos and not reflect on the tragic events that day,” university Vice President of Public Safety Adam Garcia said in a statement accompanying the release of the material in response to public records requests.

Two gunshots are heard early in more than an hour of 911 recordings that include one father calling to say he got a text from his daughter who was hiding in a classroom.

“Is there an active shooter there?” he asks.

“Yes,” the male dispatcher replies, adding that police are at the scene. “So just tell your daughter to stay where she’s at.”

New video shows campus security officers immediately entering the business school building as Las Vegas police swarm the area near the center-campus Student Union while young people stream the other way.

Video footage from a parking lot shows the gunman get out of a black sedan wearing a black trench coat and retrieve something from a passenger compartment before walking calmly toward the business school building.

A different video shows officers helping a badly wounded professor who walked out of the same building before collapsing on a sidewalk behind a patrol car.

UNLV President Keith Whitfield told the university community this month the man, a visiting professor, was “improving daily … doing rehab and out of the hospital.” He has not been identified by name.

Las Vegas police began releasing video and audio recordings in December showing officers from throughout southern Nevada spending hours going door to door in campus buildings, releasing students and faculty members in waves, before declaring the gunman had acted alone and there was no further threat.

The shooting occurred just a few miles from the site of the deadliest mass shooting in modern U.S. history: An Oct. 1, 2017, massacre that had a gunman open fire from windows of the high-rise Mandalay Bay resort into a crowd of 20,000 people at an outdoor music festival below. Sixty people died, and hundreds were wounded or injured.