LAS VEGAS >> Fire alarms blared in the background of 911 calls that police released Friday, amplifying the terrified voices of students and faculty at the University of Nevada, Las Vegas as they hid inside locked offices and under desks while a gunman fired shots outside, killing three professors.

“Someone’s shooting. Please hurry,” said one woman caller, her voice cracking with fear as she described the shots as sounding like they were next door. “I really want to go home.”

The gunman, 67-year-old Anthony Polito, walked into UNLV’s business school around lunchtime Wednesday and fired shots as he roamed the top three floors, where faculty offices are located, police said. Along with the three people who were killed, a 38-year-old visiting professor was wounded and hospitalized with life-threatening injuries.

After police killed Polito in a shootout, he was found to be carrying nine magazines for a 9 mm handgun he’d legally purchased last year and a list of targets at the school — although none of the people shot was on that list, police said.

University President Keith Whitfield said Friday that after this week’s shooting, students and faculty will not return to campus this year and final exams next week have been canceled.

“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.

The attack at UNLV terrified a city that experienced the deadliest shooting in modern U.S. history in October 2017, when a gunman killed 60 people and wounded more than 400 after opening fire from the window of a high-rise suite at Mandalay Bay on the Las Vegas Strip, just miles from the UNLV campus.

Among the first to call 911 Wednesday was a graduate student who told an operator he was locked in his office on the fourth floor and had seen an unfamiliar man walk by before the shooting started.

“A lot of shots and then screaming,” he said, describing what he was hearing. He estimated about six shots.

Several of the over three dozen calls to 911 were family members of students or faculty on campus. One woman called after hearing from her daughter about an active shooter. She described her daughter as 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 pleaded.

President Joe Biden addressed the shooting during a visit to Las Vegas on Friday, saying he was meeting with members of the university community and praying for the families of those killed.

Police still had no motive for Wednesday’s attack but said the shooter, who was a career college professor, had been denied a job at various Nevada colleges and universities and appeared to be struggling financially.

Polito arrived at UNLV in a 2007 Lexus that he parked in a lot south of the business school about 15 minutes before the shooting, said Clark County Sheriff Kevin McMahil. After leaving the car, he placed loaded magazines in his waistband and entered the business school at 11:33 a.m. The first reports of gunfire came at 11:45 a.m.

The first university officer arrived within 78 seconds of the gunfire report, and university and city police swarmed the building. A shootout erupted when UNLV officers near the main entrance saw Polito leaving the building. Officers killed the gunman about 10 minutes after the shooting rampage began.

Those killed were Patricia Navarro-Velez, 39, who taught accounting and was focused on research on cybersecurity disclosures and data analytics; Cha Jan “Jerry” Chang, 64, an associate professor in the business school’s Management, Entrepreneurship & Technology department; and Naoko Takemaru, 69, an associate professor of Japanese studies had a third-floor office in the business school building. Takemaru oversaw the university’s Japanese studies program.

It’s unclear how many shots Polito fired, but the sheriff said Polito brought more than 150 rounds of ammunition with him.

Given that number of rounds, McMahill said Polito may have intended to fire on the student union next to the business school, where students were gathered, eating and playing games.

Polito also was carrying what McMahill described as a “target list” of faculty members both from UNLV and from East Carolina University in North Carolina, where Polito taught at the business school from 2001 to 2017.

He resigned from East Carolina as a tenured associate professor, the university said.

Polito’s employment record at East Carolina did not include any disciplinary actions or red flags, according to a law enforcement official with direct knowledge of the investigation. The official was not authorized to release the information publicly and spoke to The Associated Press on the condition of anonymity.

The gunman had lived in the Las Vegas area since at least 2018.

Roseman University of Health Sciences in Henderson, Nevada, said Polito had an adjunct faculty contract and taught two courses in the school’s Master of Business Administration program from October 2018 to June 2022. He left when the program was discontinued, said 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 obsessive about 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 with Polito 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.”

Associated Press reporters Ben Finley in Norfolk, Virginia; Susan Montoya Bryan in Albuquerque, New Mexico; Ken Ritter in Las Vegas; Terry Tang and Anita Snow in Phoenix; and Robert Jablon in Los Angeles contributed to this report.