PHILADELPHIA (AP) -- Minutes after a woman was suspended from her job at a Kraft Foods Inc. plant and was escorted out, she returned with a handgun and opened fire, killing two people and critically injuring a third before being taken into custody, police said.
The shootings occurred shortly after 8:30 p.m. Thursday inside a northeast Philadelphia plant where workers for the nation's largest food manufacturer make cookies and crackers.
About 10 minutes after the woman 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.
As she walked inside, she fired a shot at an employee who had followed her in and had yelled, "Hide, she's got a gun!" Vanore said. That shot missed.
The woman then shot the three victims, said police, who didn't immediately release the victims' identities or say whether they had been targeted. Officers responded and isolated the shooter in a room, and she fired a shot at them but missed, Vanore said.
Officers freed seven people who were "in a bad position" near the woman and were hiding, said Vanore, who wouldn't refer to them as hostages. The woman was apprehended about an hour after the shootings started, he said.
Investigators, who didn't say why the woman had been suspended, were working to piece together more about what led to the sequence of events. They did not identify her.
Television footage showed workers leaving the plant, which used to be known as the Nabisco factory and is about six stories tall. Police surrounded the plant minutes after the shootings, and roads in the area were detoured as officers swarmed nearby.
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!'"
The Philadelphia Inquirer reported that about 100 people were inside the plant but had been cleared out.
Kraft said in a statement that in addition to the three employees who were shot, a contract worker suffered a less serious injury, but it did not elaborate.
"This is a sad day for the Kraft Foods family," the statement said. "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.
The Northfield, Ill.-based company's products include Oreo cookies, Philadelphia cream cheese and Oscar Mayer bacon.
Mass shootings are rarely carried out by women, said Dr. Park Dietz, a forensic psychiatrist and president of Threat Assessment Group Inc., a Newport Beach, Calif.-based violence prevention firm. But Dietz said that doesn't mean people should discount the violence potential of women.
"It was always a matter of time until we saw more incidents involving women," Dietz said in a phone interview with the AP early Friday.
Nevertheless, of the 10 to 20 multiple-victim workplace shootings in the U.S. each year, very few involve female shooters, Dietz said. They remain "a rarity," he added.
Some notable exceptions include a 1985 rampage at a mall in Springfield, Pa., that left three people dead and seven wounded. Sylvia Seegrist was found guilty of murder but mentally ill in that case and was given three life sentences. She said in 1991 she hoped she wouldn't have to spend the rest of her life in prison and "maybe 15 or 20 years would be fair."
Earlier this year, Amy Bishop, a former instructor and researcher at the University of Alabama-Huntsville, was charged with murder in a February campus shooting spree that left three biology professors dead and three other employees injured. She claimed the shootings "didn't happen."
Thursday's shootings came weeks after a driver who had been accused of stealing from a Manchester, Conn., beer distributorship shot and killed eight people and then himself.
The driver, Omar Thornton, had calmly agreed to quit on Aug. 3 after being confronted with surveillance video showing him stealing beer. But shortly afterward, he started shooting.
Thornton, who was black, told police dispatchers he had seethed with a sense of racial injustice in his job at Hartford Distributors.
But Hartford Distributors president Ross Hollander said there was no record to support claims of "racial insensitivity" made through the company's anti-harassment policy, the union grievance process or state and federal agencies. Relatives of the victims also rejected the claims.