Minutes after a woman was suspended and escorted from her job at the Kraft Foods plant in Northeast Philadelphia, she returned with a .357 Magnum and opened fire, killing two women and critically injuring a third co-worker before being taken into custody, police said.
The shootings happened shortly after 8:30 p.m. Thursday.
About 10 minutes after the Yvonne Hiller was escorted out, she returned in a car and drove through a security barrier before re-entering the building on foot, Lt. Frank Vanore said.
She walked inside, firing a shot at an employee who had followed her in and had yelled, "Hide, she's got a gun!'' Vanore said. That shot missed.
Hiller, 43, then shot the three victims, according to police -- the women were shot on the third floor and the man she confronted on the stairs as she went down to the second floor where she barricaded herself into an office.
Officers freed seven people who had locked themselves in an office next to the shooter, said Vanore.
Investigators didn't say why Hiller, a 15-year employee, was suspended. One witness told NBC Philadelphia that she has a history of run-ins with co-workers and management.
Dough mixer Andy Ryan, who has worked at the plant for nearly 30 years, said he was on the third floor when the sound of the shots echoed through the building.
"I heard the gunfire, and I ran,'' he told The Associated Press, his apron still on. "As I was running down the steps they were yelling, 'Oh, my God, there's three people shot!'''
"This is a sad day for the Kraft Foods family,'' the company said in a statement. "Our thoughts and prayers go out to their families. The loss of a loved one is a great sorrow.''
Kraft said the plant would be closed until further notice and the company would provide employees with counseling.