An intern at his first day on the job.

His two new bosses.

A mold operator. A forklift operator.

And the disgruntled coworker who brought a .40-caliber handgun to work the day he was fired — a weapon that should’ve been seized years ago due to his criminal past, police say.

Those were the employees left dead in a terrifying shooting spree Friday afternoon at the Henry Pratt Company in Aurora, during a rampage that put a national spotlight on the shocked western suburb.

Authorities on Saturday identified the company’s new human resources intern as Northern Illinois University student Trevor Wehner. Police said the 21-year-old was in the room when HR manager Clayton Parks told Gary Martin he was being let go after 15 years with the company.

Martin walked out after fatally shooting Wehner, Parks and Josh Pinkard, family members and authorities said. Operator Russell Beyer, who attended the meeting as a union representative, was also killed.

Martin also killed forklift operator Vicente Juarez in “the same general area,” Aurora Police Chief Kristen Ziman said.

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Autopsy results released Sunday showed that Beyer, Wehner and Parks all died from multiple gunshot wounds, according to the Kane County coroner’s office. Autopsies for Pinkard and Juarez were scheduled for Sunday.

Parks was an Elgin resident and a 2014 alumnus of NIU — a school that just a day before his death had marked the 11th anniversary of a mass shooting on its own campus.

“Loss like this is devastating and senseless,” NIU President Lisa Freeman said in a statement. “I ask our university community to please keep the Wehner and Parks families, friends and communities in your hearts and offer them caring thoughts.”

Wehner grew up in Sheridan in central Illinois, Freeman said. Beyer lived in Yorkville, and Juarez and Pinkard were both from Oswego.

Pinkard, who had three children, worked for Henry Pratt for 13 years and had transferred to the Aurora facility from his native Alabama last spring, according to the company.

Five police officers and a sixth employee — all of whom are expected to survive — were also wounded in the attack carried out by a gunman with a felony conviction which should have prevented him from possessing a weapon, Ziman said.

The five officers — who were fired on almost immediately upon arriving to multiple calls of an active shooter at the water valve manufacturing plant at 641 Archer Ave.— range in age from 23 to 53. Three of the officers have at least 24 years of service with the department.

Two officers underwent surgery Friday, and the three others were treated and released by Saturday morning, police said. Their names have not been released.

Court records show Martin was convicted of aggravated assault in the stabbing of a woman in Mississippi in 1995. He’d also been arrested six times previously by Aurora police, most recently in 2008 for violating an order of protection, Ziman revealed Saturday.

Ziman said the assault conviction might not have appeared on a criminal background check when Martin applied and was approved in January 2014 for a Firearm Owners Identification card.

In March of that year, Martin applied to buy a handgun from an Aurora gun dealer, and he was approved within five days.

Five days after that, Martin applied for a concealed carry permit. When Martin’s felony conviction was discovered during the background check for that license, his application was denied and his FOID card was revoked.

However, his Smith & Wesson handgun — the same weapon used in Friday’s shooting — was never confiscated.

Ziman said authorities are investigating why Martin was able to keep the firearm.

Authorities on Saturday also detailed the timeline of the attack that prompted a massive police response and a 90-minute standoff. It ended with a SWAT team tracking down Martin in the 29,000-square foot warehouse and killing him in an exchange of gunfire, police said.

Authorities received the first calls for an active shooter at 1:24 p.m. and officers arrived four minutes later.

At 1:30 p.m., the first officer was struck by gunfire, authorities said. Three more officers were shot within the next five minutes.

At 1:31 p.m., a police armored tactical vehicle breached the building to help officers get inside. The wounded officers were picked up by police as SWAT teams continued searching for the shooter.

About 90 minutes later, officers shot and killed Martin.

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A woman who identified herself as Martin’s mother told the Sun-Times on Friday that he was “way too stressed out” after being laid off about two weeks ago.

“Something happened to set this off,” Andy Williams Jr., a friend of Martin’s since childhood, said at a vigil for the victims. “Shouldn’t we pray for Gary’s family too? His mother’s at home suffering.”

Scott Hall, the president and CEO of the parent company of Henry Pratt, said Saturday that Martin had been set to be fired for a “culmination of various workplace rules violations” — though none of them indicated he could be violent. Hall declined to specify what those violations were, citing the ongoing investigation by Aurora police.

Nine people were in the warehouse at the time of the shooting, Hall said.

He also said that Martin’s background check — performed when he was hired 15 years ago — did not show his Mississippi conviction.

“We will look at what we could have done differently in the days and weeks ahead,” Hall said.

An online fundraiser verified by GoFundMe and the City of Aurora had raised thousands of dollars for the shooting victims within a few hours.