FRESNO, Calif. (AP) — Clattering machinery at a chicken-processing plant provided all the cover Lawrence Jones needed to kill two co-workers execution style and wound two others Tuesday, police said.

Armed with a handgun, the 42-year-old parolee moved methodically from victim to victim, placing his handgun against their head or neck and then pulling the trigger, authorities said.

The unsuspecting victims worked just feet apart in the deboning room and the grinding room at Valley Protein, but they wore ear protectors and the gunshots were drowned out by the machinery.