As police continue to investigate a possible motive in Wednesday's mass shooting at the University of Nevada, Las Vegas, details are emerging from recordings of 911 calls from people on campus during the attack.

Police on Friday released dozens of recordings of calls to dispatchers from panicked, fearful students and staff, as well as family members of people stuck on campus.

Three UNLV professors were killed in the shooting and a fourth is hospitalized with life-threatening injuries. On Friday, the identity of the third professor who was killed was released.

The victims were Naoko Takemaru, 69, who taught Japanese Studies at UNLV; Patricia Navarro-Velez, 39, who taught accounting; and Cha Jan "Jerry" Chang, 64, who taught information systems. All three slain professors had offices at Beam Hall.

The gunman was killed by police after he fired at officers, officials said.

University President Keith Whitfield said Friday that final exams had been canceled and students and faculty would not return to campus until after the holidays.

“Given the physical and emotional trauma that the university community has endured, and because of the impact to campus facilities, we have decided that faculty and staff should continue to work remotely through the end of the calendar year,” Whitfield said in a letter to students and staff.

Police still had not identified what spurred Wednesday's attack but officials said the shooter, who was a career college professor, had been denied jobs at various Nevada colleges and universities and appeared to be struggling financially. The gunman, 67-year-old Anthony Polito, was carrying a list of people he apparently planned to target during the shooting, police said. But none of the people shot on Wednesday was named on the list, according to authorities.

Here's what we know about how the shooting unfolded:

Students trapped in offices, calls from concerned family members

Polito arrived at UNLV about 15 minutes before the late morning rampage began, parking in a lot south of the business school, said Clark County Sheriff Kevin McMahill. After he got out of the car, he placed loaded magazines in his waistband and entered the business school at 11:33 a.m. Wednesday.

Students who feared for their lives began calling 911 minutes later, around 11:45 a.m., saying they'd heard gunfire.

One of the first people to call emergency responders was a graduate student who told the 911 operator he was locked in his office on the fourth floor of the business school. The gunman visited each of the business school's top three floors, which is where faculty offices are located, police said.

On the call, the student said he had seen an unfamiliar man pass by before he heard gunshots.

“A lot of shots and then screaming,” the student said, saying he heard about six shots.

In a 911 call logged at 11:49 a.m., a woman on the second floor of the business school said she saw the shooter and his gun, the Las Vegas Review-Journal reported. The woman said she had heard gunshots and briefly saw a man with a handgun before she locked the door to a classroom where she and others were hiding.

More than three dozen calls came in to 911 calls reporting the shooting. Many came from family members of students who were on campus, according to the AP.

One mother called after learning from her daughter there was an active shooting on campus. She said her daughter was hyperventilating and crying.

“She just called me and she can’t even breathe. Can you call her back or something? Can you investigate,” the woman said.

The Associated Press did not name the woman or provide updated information about her daughter.

Police killed gunman minutes after victims shot

The first university officer arrived within 78 seconds of the gunfire report, and university and city police officials swarmed the building, McMahill said.

A shootout between the gunman and police erupted near the main entrance, the sheriff said. Two officers spotted Polito leaving the building and fired at him, killing him about 10 minutes after he'd fired his first shot.

UNLV mourns slain professors: 'lionhearted,' loving, 'rigorous'

UNLV President Keith Whitfield remembered the three professors killed on campus Wednesday, noting the depth of the community's loss.

"Processing the loss of three cherished UNLV faculty members is horrendously difficult, but we are heartened by memories of them and their remarkable and lasting impact on our university, on their students, and within their professions," he said in a statement on Friday.

Funeral arrangements for Navarro-Velez, Chang and Takemaru have not yet been made public.

French professor Margaret Harp recalled Takemaru for the breadth of artistic talents. Takemaru played the piano, embroidered and gave out homemade chocolates every holiday season. She was hired in 2003 to develop the Japanese language program, Harp said, and succeeded in always having a full class.

“Naoko was frail physically. However, she was lionhearted in kindness, lionhearted in generosity, lionhearted in humanity – the point of liberal arts,” Harp said. “And I have no doubt she was lionhearted in her final moments on earth."

Accounting professor Jason Smith remembered Navarro-Velez for her “larger-than-life personality, an infectious smile and a genuine kindness that made everyone around her feel like family.” 

Smith said she was known for her baking talents, especially her crème brûlée and macarons, and her love of gatherings. “‘The more the merrier,’ she would say,” Smith recalled.

Navarro-Velez had worked at three universities and then took on a role at one of the world’s largest public accounting firms, he said. She'd returned to the classroom as a professor to share her love for the field.

Business professor Keah-Choon Tan met Chang in 2001 and recalled ice fishing trips with him and the two professors' kids in the early years of friendship. In one of the excursions, Tan said they were both pulled over at the same time by the same trooper and both received speeding tickets. “We learned our lesson,” Tan said through laughter.

“Jerry was a rigorous researcher and a good teacher who deeply loved his students at UNLV,” he said.

The Lee Business School at the university has created memorial scholarships in Navarro-Velez' and Chang's names for accounting and information systems. To donate, visit ifolio.cloud/UNLVStrong.

Gunman had massive cache of ammunition

Authorities have not determined how many shots Polito fired, but the sheriff's office reported he arrived on campus Wednesday with more than 150 rounds of ammunition.

The sheriff said Polito was carrying a "target list" of faculty members from UNLV. The list also included faculty members at Eastern Carolina University in North Carolina, where the gunman taught from 2001 to 2017.

No red flags in Polito's employment records

Polito's work record during his time at East Carolina University didn't include any disciplinary action or other red flags, a law enforcement official with direct knowledge of the investigation told the Associated Press. The official was not authorized to release the information publicly and spoke to reporters on the condition of anonymity.

Polito resigned from East Carolina as a tenured associate professor in 2017, officials at the school said. He moved to Las Vegas in 2018, according to his employment records.

Polito worked as an adjunct instructor at Roseman University of Health Sciences in Henderson, a Las Vegas suburb. He taught two courses in the school's Master of Business Administration program and ended his employment on the campus in June 2022, the school said. He left when the program he was teaching in was discontinued, according to Jason Roth, a school spokesperson.

A former student at East Carolina, Paul Whittington, said Polito often talked about his regular trips to Las Vegas. He also seemed to be obsessed with anonymous student reviews, Whittington said.

“He always talked about the negative feedback he got,” said Whittington, now 33, who took an introductory course in operations management Polito taught in 2014. “He didn’t get a lot of it, but there would always be one student every semester, or at least one student every class, that would give a negative review.”

Contributing: Zachary Zchermele, Michael Collins and Minnah Arshad, USA TODAY; Associated Press.