Three men are dead, three others are in critical condition and at least two other people were hurt in a workplace shooting at a Southern California Edison office in Irwindale, according to the Los Angeles County Fire Department.

The unidentified gunman shot and killed himself after opening fire in the office complex, said Irwindale Police Chief Dennis Smith. The gunman reportedly used a semi-automatic handgun.

Early reports noted the gunman was a Southern California Edison employee, but that has yet to be confirmed. However, the company is confirming that all victims were associated with the utility company.

Dozens of people were seen leaving the building in a single-file line, holding their hands in the air hours after the incident occured at about 1:30 p.m. at 4910 Rivergrade Road.

"We heard a lot of sirens and helicopters overhead. We heard over the PA system that there was an emergency," said Tammy Gann of the San Gabriel Valley Economic Partnership, which works in the same building.

Authorities said they are combing the rooms of the three-story office complex which requires an authorized card swipe to enter the building.

Southern California Edison locked down all of its facilities this afternoon upon learning of the gunman, but those restrictions have since been lifted on all but the Rivergrade facility, which was almost exclusively information technology-based.

One man told NBC4 News that he received texts from his daughter who was in the building at the time.

“The shooter was working today and talked to my big boss five minutes before he started shooting,” the man said, reading the message on his phone.

Another man with a relative in the building said she texted him to tell him that two people had been shot. The worker told him the gunman walked in and told a manager he was going to shoot him before opening fire.

Two nearby schools were placed on lockdown due to police activity.

Around 2:30 p.m., students at Walnut Elementary School were dismissed, said Cynthia Cuevas, Baldwin Park Unified School Assistant Superintendent.

Olive Junior High School, which was also on lockdown, began a staggered release around 3 p.m. Parents can pick up their children at the Main Street entrance.

"Your children are safe," said Cuevas.





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