A grand jury has declined to bring charges against an off-duty police officer who fatally shot a man with mental illness inside a Southern California Costco, Riverside County District Attorney Mike Hestrin said at a Wednesday news conference.

Hestrin said he wasn’t sure why the panel had declined to indict Officer Salvador Sanchez, who shot and killed 32-year-old Kenneth French, a nonverbal man with schizophrenia, during the June 14 incident in Corona. But Hestrin said French had attacked Sanchez from behind while the off-duty officer ― a seven-year veteran of the Los Angeles Police Department ― was holding his 1½-year-old son in a food-tasting line, AP reported.

The officer, Hestrin said, believed that he’d been shot in the head and that an active shooter was on the loose. Sanchez fired 10 rounds of his handgun, fatally striking French and critically wounding French’s parents, Russell and Paola French. Neither French nor his parents were armed.

“It was out of the blue and the officer wasn’t expecting it,” Hestrin said of French’s attack of Sanchez, according to CBS News. “He’s hit in the back of his head while he’s holding his child in his hands ... I can only imagine those facts played into the jury’s decision here.”

DA Mike Hestrin announces grand jury finding in Corona Costco shooting case.



Click link to see news release: https://t.co/U8OV2thy4d



Press conference can be seen on Facebook: https://t.co/2DmEkHtMEF pic.twitter.com/h8MM4SMbdM — Riverside County DA's Office (@RivCoDA) September 25, 2019

During the news conference, Hestrin played a grainy surveillance video that investigators had relied on during their probe of the incident. As the Los Angeles Times noted, however, the footage is of such low quality that it’s difficult to decipher what exactly is happening in the clip.

The video appears to show French, wearing a striped shirt, being pulled across the store by a male family member before the pair fall one at the time to the ground. “Sanchez is barely visible in the far-left frame,” the LA Times said.

Prosecutors said the incident happened very quickly, with Sanchez firing his weapon less than four seconds after he was hit.

The officer, who remains on paid administrative leave as the LAPD conducts an administrative inquiry into whether he followed department policies, reportedly suffered minor injuries in the incident. His child was not hurt.

The off-duty @LAPDHQ officer who fatally shot #KennethFrench, a schizophrenic man, will not face criminal charges. I spoke to the French Family's attorney who reacted to @RivCoDA's press conference. FULL STORY: https://t.co/LMk53eoP0G pic.twitter.com/juo4cQhG4h — Vicky Nguyen (@VickyNguyenNews) September 26, 2019

Dale Galipo, an attorney for the French family, has acknowledged that French pushed or slapped Sanchez’s back. French had been off his medications due to other health complications, the lawyer said, which may have affected his behavior that day.

Still, Galipo said the shooting had not been a justified response to French’s actions.

The attorney said French’s father had stepped between his son and Sanchez immediately after the attack, and that both French’s dad and mom had tried to explain to the officer that their son had a mental disability, CBS News reported.

“I told Officer Sanchez not to shoot, twice, I even said ‘please,’ I was pleading for our son and our lives,” Paola French said at an August news conference.

The family is planning to file a federal lawsuit over the shooting within the next month, AP reported.

Ira Salzman, Sanchez’s attorney, said Wednesday that the officer was “gratified” by the grand jury’s decision.

“Sal believed he was shot,” Salzman said. “The case was a terrible tragedy.”

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