LAS VEGAS (KLAS) — Las Vegas Metro police began releasing body-camera videos Wednesday of officers responding to a mass shooting at the University of Nevada, Las Vegas, which left three professors dead and a fourth injured.

Professor Cha Jan “Jerry” Chang, 64, of Henderson; Associate Professor Naoko Takemaru, 69, of Las Vegas, 69; and Assistant Professor Patricia Navarro Velez, 39, of Las Vegas, were killed on Dec. 6.

Responding UNLV officers shot and killed the gunman, Anthony “Tony” Polito, 67. A fourth professor was also shot and survived.

One hour-long video released Wednesday afternoon shows an officer running to the outside of Beam Hall where Polito’s body was lying. There appears to be initial confusion about a possible second shooter inside.

“Active shooter scene,” an officer says in a radio call recorded via a second officer’s body camera. “Let’s make our way to the suspect and take him out.”

The video continues as officers search offices and classrooms, kicking in doors and clearing hallways. A second video shows a similar scene.

Another part of a video includes a dispatcher relaying Polito’s name as a suspect, though by that time, he was already deceased.

“The UNLVPD’s possible suspect is a Polito, Anthony,” the dispatcher says.

“Anthony Polito’s our suspect,” an officer then says.

Polito, a long-time professor who was turned down for a job at the university, lived in a Henderson apartment. In a 15-page thesis, Polito took credit for decoding 18 characters, which he claimed identified as the Zodiac Killer, who used a code of symbols to communicate with police. Police never arrested anyone in the case.

Polito’s online presence depicted him as a scholar. His website listed his resume and educational achievements, including an MBA from Duke University and a Ph.D. from the University of Georgia.

LVMPD Sheriff Kevin McMahill said Polito had been “struggling financially” and that police found an eviction notice on his door. Polito wrote a list of people to target on campus, and 22 letters officials say Polito sent to University personnel across the country, one of which that was intercepted contained an “unknown white powder substance.”

The release comes after several public records requests from media organizations, including 8 News Now. More videos were expected to be released in the coming days.

The videos are provided with redactions and blurred faces.