California meat plant shooting: 3 dead, 2 injured in Fresno (VIDEO)

Fresno Police Chief Jerry Dyer speaks to the media about a shooting at a local chicken plant Nov. 6, 2012, that left 3 people dead, including the gunman.

Three people were killed, including the gunman, and two injured in a shooting Tuesday at a chicken plant in Fresno, California.

Police told The Associated Press they didn't know what prompted Lawrence Jones, 42, to start shooting before turning the gun on himself midway through his shift at Valley Protein, formerly known as Apple Valley Farms.

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Jones had worked at the plant for 14 months. He clocked in as normal at 4:58 a.m. Tuesday, but co-workers told police he seemed "off."

"According to one of his coworkers, he did not appear to be himself when he came to work," Fresno Police Chief Jerry Dyer was quoted by ABC News as saying at a news conference following the shooting.

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Jones was found lying on the sidewalk outside with a gunshot wound to the head. He and one of the victims died at a local hospital, the Fresno Bee reported.

A third victim died at the scene.

Jones had an extensive criminal history dating back to the 1990s, although police would not elaborate.