A man about to go to prison for stealing engine parts from the factory where he had worked for nearly 40 years forced his way into the plant near Chicago and opened fire, killing four people before taking his own life. Four others were wounded, two critically, in the latest of a plague of violent attacks at work, in schools and in other public places in the United States. Police said William Baker, 66, showed up at the plant with an AK-47 assault rifle, a pump-action shotgun, a hunting rifle and a revolver stashed inside a golf bag. He forced his way past a security guard and walked up and down aisles on the factory floor, shooting randomly. He ended up in an office where he shot his final victim and then himself, Reuters reports.