The University of Nevada, Las Vegas is mourning three people after a deadly shooting by a former college professor.

Police shot and killed the gunman, 67-year-old Anthony Polito. He had previously taught in North Carolina and Georgia. The Associated Press recounts that he had applied for a job at UNLV.

However, law enforcement has denied certainty of motive and said he used a handgun to commit these crimes. ABC News reports that police are searching Polito's home for evidence regarding motive. It is not clear whether he knew his victims.

The outlet also learned from Polito's personal webpage and LinkedIn profile that he once published research on the Zodiac Killer, the Northern California mass killer from the late 1960s. Polito claimed to have decoded some of the infamous cryptic messages associated with that criminal.

Las Vegas Police chief Kevin McMahill on Wednesday told reporters that a fourth victim is in stable condition at a local hospital. Four others were treated at hospitals for panic attacks, while two officers were treated for minor injuries.

University police chief Adam Garcia praised first responders for their rapid response to emergency calls of shots fired on campus. The local ABC News station interviewed a student who was on campus throughout the incident and who said that the police response was impressive.

The names of victims have not been released as of this writing, but the school has confirmed that they were faculty and staff. No students were harmed. Campus is closed today and tomorrow.