FRESNO, Calif. – The ex-convict accused of shooting several co-workers execution-style at a Fresno chicken-processing plant, killing one, was described by his boss as a model employee who was given an award for his punctuality.

But records show 42-year-old Lawrence Jones, who fatally shot himself, had also been in and out of prison for crimes ranging from armed robbery to car theft. Authorities say they haven’t determined what sparked Tuesday’s rampage.

Valley Protein president Bob Coyle says none of the employees was aware of any animosities between Jones and others.