The disgruntled professor who shot four educators at the University of Nevada, Las Vegas - killing three - had taken a powerful erectile dysfunction drug before going on his rampage.

Anthony Polito, 67, opened fire on the fourth floor of the Lee Business School at 11.45am on December 6, killing Professors Patricia Navarro Valez, 39; Cha Jan 'Jerry' Chang, 64; and Naomo Takemoru, 69, and critically injuring a fourth.

He then died in a shootout with police who rushed to the scene.

An ensuing autopsy report has since revealed that Polito had tadalafil - the scientific name for Cialis - in his bloodstream, the Las Vegas Review-Journal reports.

Polito's bloodstream tested positive for 84 nanograms per milliliter of the erectile dysfunction drug - which can last up to 36 hours in the body, according to the autopsy report on June 15.

University of Nevada, Las Vegas gunman Anthony Polito, 67, had oxycodone and erectile dysfunction drugs in his system when he was shot down by police in December

Polito's bloodstream tested positive for 84 nanograms per milliliter of Cialis

He also tested positive for oxycodone, with 15 nanograms per milliliter in his bloodstream - far below the US Department of Transportation testing threshold of 100 nanograms per milliliter for urine tests.

Neither Cialis nor oxycodone are known to increase risk-taking behavior the way alcohol does, Matthew Johnson, a Johns Hopkins University specialist who studies psychological effects of drugs, told the Review-Journal.

He also noted that it is unclear whether Polito took the oxycodone shortly before his death, or if he had taken a large amount in the past.

It is believed Polito opened fire on the Las Vegas campus after feeling jilted that he was rejected from a teaching position at the school. 

He had been obsessed with Sin City, his former students have said, and had applied to several jobs at various colleges and universities across Nevada - but was denied the job each time. 

Polito targeted the university's business school after allegedly feeling jilted that he was rejected a job opportunity 

The shooting spurred a large police presence on the Las Vegas campus

On the day of the attack, police said Polito went to several floors of the business school before he was killed in a shootout with two university officers outside the building.

The officers were later identified as  Det. Nathaniel Drum, who has been employed with the University Police services since 2017, and officer Damien Garcia, who has been on the force since 2018.

'These two officers are heroes,' Adam Garcia, police chief for 시알리스 구매 사이트 the University Police Services Southern Command 시알리스 효과 said in the aftermath. 

'They kept the worst from becoming a bloodbath.' 

Polito's body was later found in front of the Frank and Estella Beam Hall, with  a legally-purchased 9mm handgun and 11 loaded magazines on him, and several pouches containing nine additional magazines.

 Naoko Takemaru, 69, associate professor of Japanese studies was killed in the shooting 

Patricia Navarro-Velez, an assistant professor at the UNLV accounting department, 시알리스 효과 and Jerry Changn (right) were also shot dead by Polito

He had already been armed with 150 rounds of ammunition, the Review-Journal reports.

Investigators also found what appeared to be a target list - a laminated notecard with names and room numbers on them, according to the autopsy report.

Officials announced in the days following the shooting that they had contacted everyone on the list, except for 시알리스 효과 one person who was on a flight.

'None of the individuals on the target list became a victim,' Sheriff Kevin McMahill said.

As the massacre unfolded, the university alerted students to 'RUN-HIDE-FIGHT'

Students were seen evacuating the university as shots rang out in December

As the massacre unfolded, the university issued an alert to students, warning them to  'RUN-HIDE-FIGHT.' 

A huge police presence including tactical teams immediately deployed to the scene, searching for the suspect, as the school was put on lockdown.

Less than an hour after the alert was released, the Las Vegas Metropolitan Police Department announced the suspect was deceased, and footage showed terrified students being gradually escorted out of buildings across the campus. 

Las Vegas