(CNN) California prosecutors won't file charges against an off-duty officer who fatally shot a man three months ago inside a Costco store in Corona.

Following a grand jury decision that charges are not warranted, Riverside County District Attorney Mike Hestrin will not file criminal charges against Salvador Sanchez, a Los Angeles police officer, Hestrin announced Wednesday.

Kenneth French, described by a cousin as nonverbal, is believed to have struck Sanchez, who then fired 10 shots. Sanchez was shopping with his family on June 14 and holding his young child when the brief incident began.

French, who had been diagnosed with schizophrenia, was unarmed.

French was hit three times in the back and once in the shoulder, said Joe DelGiudice, chief of investigations for the district attorney's office.

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