MELROSE, Ill. — The man who went on a murderous rampage before killing himself at a Chicago-area Navistar factory has been identified as William Baker, 66, formerly of Carol Stream, Ill.

The disgruntled ex-employee was supposed to begin a five-month jail term, which was to be followed by five months of home confinement, for his part in an engine theft scheme.

Baker had been charged in September 1999 with conspiracy to commit theft along five other co-conspirators, according to Beth Needles, a spokesperson for the Chicago department of the U.S. Attorney’s Office.

Baker apparently arrived at the plant with a complete arsenal of weapons hidden in a golf bag. He forced his way into the facility with a .38-calibre revolver after a security guard attempted to prevent him from entering.

With his AK-47 assault rifle blasting away, Baker moved through the plant killing three workers in the engineering area. He then entered the office area and killed another individual before taking his own life.

Initial police reports indicate that at least four others were wounded in the incident, which took place yesterday around 10 a.m. central time.

Michael Kalagian, a Navistar engineer who fled when the shooting erupted, told local media at the time of the massacre that while he didn’t see the gunman, some of his co-workers had recognized the man as a former employee.

“I just heard several, several gunshots,” said Kalagian. “I heard, I heard three, three initially, and then when I was running for the exit I heard about three, three, four more.”

The company has identified the dead as the gunman, Baker; Daniel Dorsch, 52, a lab supervisor; and Robert Wehrheim, 47, a lab technician. The names of the other two victims are not being released at the request of the families.

The Navistar plant is located some 15 miles from the company’s downtown Chicago headquarters and employs about 1,400 people.