CHICAGO (CBS) — A gunman opened fire inside an Aurora manufacturing plant on Friday, killing five people and wounding six police officers. None of the victims names had been released as of Friday night.

The suspect, identified as 45-year-old Gary Martin, exchanged gunfire with police as soon as officers entered the 29,000 square-foot Henry Pratt building around 1:30 p.m. Feb. 15.

A total of 12 people, including the gunman, were shot. The five wounded police officers, all men, were shot within five minutes of arriving on the scene, according to Aurora Police Chief Kristen Ziman.

All the victims who died were employees. A sixth person employee was being treated in a hospital for non life-threatening injuries.

Martin lived in Aurora and was employed at the company, a subsidiary of Mueller Water Products, for 15 years. The Atlanta-based company manufactures water measurement products, according to its website.

The motive of the shooting was still unclear, but Ziman said Martin had recently been fired and had returned to his former employer Friday in an attempt to get his job back.

Records show Martin was sentenced in February 1995 in Mississippi on an aggravated assault offense.

In a statement released Friday night, the company said it was left “shocked and deeply saddened by the horrific tragedy.”

“Our 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,” the statement reads. “Our entire focus is on the health and well-being of our colleagues, and we are committed to providing any and all support to them and their families.”

Ziman said police were notified about the shooting at 1:24 p.m. They arrived on the scene at 1:28 p.m. and were immediately fired upon.

Five officers were shot. A sixth suffered a knee injury.

At a press conference, Aurora Mayor Richard Irvin said the following:

“I don’t think I can be clearer in saying today is a sad day. We have seen similar situations around our nation. But to experience it first hand is even more painful. A shame these shootings are commonplace, a shame that someone would be so selfish to think he has the right to take an innocent life. We as a society cannot allow the heartless acts to become a spot on the 10 o’clock news.”

Gov. JB Pritzker also attended the press conference.

“There is no way to prepare for the pain of losing innocent people,” Pritzker said. “In the state that you were elected to lead, the state that you were elected to protect, there is no way to prepare. There are no words for the kind of evil that robs our neighbors of their lives.”

CONFIRMED: of 5 officers shot — 3 – shot in the lower body

1 – shot in the neck

1 – shot in eye / shrapnel All were hospitalized. 2 airlifted to trauma centers. #AuroraShooting @cbschicago — Brad Edwards (@tvbrad) February 16, 2019

Two officers were shot in the leg; another in the hip; one in the neck and a fifth officers was hit in the neck. The injuries are all described an non life-threatening.