Authorities identified the gunman in mass shooting Friday as 45-year-old Gary Martin.
He opened fire at Henry Pratt Co. in the Chicago suburbs of the Aurora, shooting at terrified employees before engaging in a gunbattle with responding officers
All five employees who died in shooting were men, police said. The shooter was killed during an exchange of gunfire with law enforcement officials, Aurora Police Chief Kristen Ziman said.
Martin, who worked at the company, was being released on the same day, police said. They did not provide additional details on why he was losing his job or whether he had been notified before shooting.
John Probst, an employee who survived the shooting, told CNN affiliate WLS that the gunman was a coworker.
He was "running down the aisle" with a gun that had a green laser sight on it, he said.
"As soon as I saw the green thing and heard the shots, we left," said Probst, who has been working at the plant for 40 years. "It was just shooting everybody."
Probst said one of the victims who ran out with his arms bleeding told the gunman "went balistic."
90 minutes of terror
It took about 90 minutes after the rampage began to control the situation.
A police shooter has been called in for an active shooter, and police arrived at the scene four minutes later and surrounded the facility, Ziman said. When officers stormed the 29,000-square-foot building to look for the gunman, he fired at them.
"Additional officers started to arrive and were also fired upon," Ziman said. Five officers were struck by a gunfire and a sixth officer was injured in his knee and needed to go to a hospital. All the injured officers were shot within the first five minutes of responding, Ziman said, and their injuries are not life-threatening.
Henry Pratt Co. describes itself as one of the nation's largest manufacturers of industrial valves. "My hearts are with the victims and their loved ones, the first responders, the Aurora community and the entire Mueller family during this extremely difficult time, "
" Our entire focus is on the health and wellbeing of our colleagues, and we are committed to providing any and all support to them and their families. "
A task force from the Kane County Sheriff's Office will investigate the gunman's death, Ziman said.
Authors have not identified the victims in the nation's latest mass shooting. But the police said all the victims – both employees and police officers – were male.
Illinois Gov. J.B. Pritzker, who was sworn in office just over a month ago, thanked law enforcement officials.
"There is no way to prepare. There are no words for the kind of evil that robs our neighbors of their hopes, their dreams and their futures," he said in a statement. "There are no words to express our gratitude to the families of the officers who were injured in the line of duty as they responded within moments to the gravest kind of danger that they could do."
Aurora Mayor Richard Irvin said mass shootings have become all too common in the nation.
"It's a shame that a cold and heartless offender would be so selfish as to think he has the right to take an innocent life.
Shocked neighbor speaks out
Martin's next-door neighbor said he moved to the apartment complex over the summer. She said she was not close with him, but the two would say hi in passing.
"He seemed very friendly, he said hi to a lot of people who came and gone, I'm kind of shocked I guess," said Mary McKnight. "I'm sad and shocked, and you never know."
Aurora is the second-largest city in Illinois, and has a population of about 200,000 people