New details in a deadly shooting at a Costco store in Southern California on Friday night reveal an off-duty Los Angeles Police Department officer opened fire when a man assaulted him while he was holding his child, authorities said.

The off-duty officer shot and killed the alleged attacker, identified as Kenneth French, 32, and struck two of his family members. Both were in critical condition. The attack on the officer was apparently unprovoked.

COSTCO STORE GUNFIRE LEAVES 1 DEAD, 2 INJURED IN SOUTHERN CALIFORNIA

The officer, whose name was being withheld, fired several shots, according to witnesses, prompting scared shoppers to run for the exits.

"I saw people and heard shots and my first thought was 'Jesus, is this another mass shooting?'" witness Nikki Tate told the Associated Press. She and her daughter huddled on the ground until they were able to get out a side door.

"I didn't know if this was a random thing or a domestic thing or if this was a mass shooting," she said. "Everything was happening so fast, I just wanted to get me and my kid to safety."

The LAPD said it has launched its own investigation. The officer’s gun was the only weapon recovered at the scene. Police said the two men did not know each other.

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Police originally said a suspect was in custody Friday but later confirmed that no one had been charged.

The Associated Press contributed to this story.