Yvonne Hiller, 43, was escorted from the plant after being told of the suspension about 8:30 p.m. Thursday. But she returned from her vehicle with a .357 magnum, threatened a guard with her gun to get past security, and made her way to the third floor, where she found her victims in a break room, police said.
Hiller told one woman she was free to leave, then fired just three shots, one at each victim, Homicide Capt. James Clark said.
Hiller had been involved in a series of arguments and a few physical altercations in recent years in the mixing area where she worked, police said.
After leaving the break room, Hiller went down a hallway and fired shots at the supervisor who had suspended her along with an employee who was using a walkie-talkie to alert police and co-workers to her whereabouts, police said. She missed both of them.
Hiller then went to a second-floor office, where she called police to tell them what she had done. She had put her gun down by the time officers found her there, Clark said.
The victims were identified as Tanya Renee Wilson, 47; Latonya Sharon Brown, 36; and Bryant A. Dalton; 39, all of Philadelphia. Wilson and Brown died at the plant.
Dalton, shot in the neck, was in critical condition at Jefferson University Hospital, police said.
Hiller was charged with two counts of murder, one count of attempted murder, aggravated assault and other charges. She had a permit to carry the gun, authorities said.
Hiller has worked for Kraft for about 15 years. The Northfield, Ill.-based company makes Oreo cookies, Philadelphia cream cheese, Oscar Mayer bacon and other products.