Last Updated Sep 20, 2018 9:32 AM EDT
MIDDLETON, Wis. -- A shooter opened fire inside a Wisconsin software company Wednesday, seriously wounding three people and grazing a fourth before responding officers fatally shot the assailant. Workers ran from the office building or hid inside, according to police and witnesses.
Officers were alerted to an active-shooter situation at WTS Paradigm around 10:25 a.m., said Middleton Police Chief Chuck Foulke. The suspect was taken to a hospital after being shot by officers but later died, said Foulke.
Foulke didn't release details about the suspect, a possible motive or how the attack unfolded in Middleton, a city just west of Madison. He said there were no other suspects.
Judy Lahmers, a business analyst at WTS Paradigm, said she was working at her desk when she heard what sounded "like somebody was dropping boards on the ground, really loud." Lahmers said she ran out of the building and hid behind a car. She said the building's glass entrance door was shattered.
"I'm not looking back, I'm running as fast as I can. You just wonder, 'Do you hide or do you run?'" she told The Associated Press.
She said she knew one co-worker had been grazed by a bullet but was OK. She didn't have any other information about the shooting, but said it was "totally unexpected. We're all software people. We have a good group."
Two hospitals in Madison said they were initially treating five people from the shooting: one who was in critical condition early Wednesday afternoon, two who were in serious condition, and one whose condition wasn't released. The fifth person was a walk-in patient who was treated and released. It wasn't immediately clear if one of those patients was the shooter.
Police said businesses at and near the scene of the incident will be closed for the next 24 to 48 hours during an ongoing investigation, CBS affiliate WISC-TV reported.
Police conducted a secondary search of the office building early in the afternoon to ensure there were no more victims or suspects -- and officers discovered some people still hiding in the building, which also houses Esker Software.
Middleton city administrator Mike Davis said the situation was considered stable at about 12:40 p.m. local time.
Gabe Geib, a customer advocate at Esker Software, said he was working at his desk when he heard what "sounded like claps." He said he then saw people running away from the building at "full sprint."
"We knew at that point that something was going down. A ton of people were running across the street right in front of us," he said.
Geib said he and his colleagues were still huddled in their cafeteria, away from windows, more than an hour after the shooting.
WTS Paradigm makes software for the building products industry. A Wisconsin State Journal profile from 2014 listed company employment at about 145 employees, and noted the company was looking to move to a larger location at the time. The company's website was down Wednesday.