PHILADELPHIA – A Kraft Foods plant worker who had been suspended for feuding with colleagues, then escorted from the building, returned minutes later with a handgun, found her foes in a break room and executed two of them with a single bullet each and critically wounded a third, police said Friday.

Yvonne Hiller, 43, had gotten into an argument Thursday evening with her co-workers at the northeast Philadelphia plant, police said. After she was disciplined, she went to her vehicle, made several phone calls, then grabbed a .357 Magnum and used it to force her way past security guards at the front gate.

About 100 people were at work at the plant, which makes Nabisco cookies and crackers.

Hiller walked to the third-floor mixing area and found four people in the break room. She had no quarrel with one woman and told her to leave. She then opened fire on the others, Philadelphia Homicide Capt. James Clark said.

“She believed they were spraying chemicals at her, saying things behind her back,” Clark said.

After leaving the break room, Hiller went down a hallway and fired her gun at the supervisor who had suspended her and at a mechanic who was using a walkie-talkie to alert police and co-workers to her whereabouts, police said. She missed both.

Hiller finally went to a second-floor office and called police to tell them what she had done, authorities said. Seven other workers were hiding in a closet nearby.

Cpl. Janice Leader, a 911 dispatcher, told reporters Friday that Hiller called 911, saying “I’m the one you’re looking for” and reporting that she had been harassed at work.

Police called the mechanic a hero who “did a phenomenal job” in alerting employees to evacuate the building and directing officers to where Hiller was.