Exactly how badly was off-duty Los Angeles police Officer Salvador Alejandro Sanchez injured on June 14, 2019, when an intellectually disabled man slugged him in the head from behind without warning while in the line for meat samples at the Costco in Corona?

The blow, Sanchez has said, knocked him unconscious and prompted him to subsequently fire the shots that killed Kenneth French, 32, and critically wounded his parents, Russell and Paola.

Sanchez has pleaded not guilty to one count of voluntary manslaughter and two counts of assault with a deadly weapon. He is being prosecuted by the state Attorney General’s Office after the Riverside County Grand Jury declined to indict him and District Attorney Mike Hestrin, who said he had reservations about the legitimacy of the shooting, decided not to file charges.

Superior Court Judge Samuel Diaz Jr. will decide at the end of the preliminary hearing whether there is sufficient evidence to hold Sanchez for trial.

On the first day of the hearing on Wednesday, Sanchez’s attorney and a state prosecutor focused on Sanchez’s fall while wading through testimony from two forgetful witnesses who often contradicted their 2019 testimony before the grand jury. After the hearing was continued to Thursday, defense attorney Michael D. Schwartz declined to comment on the focus on how Sanchez fell after he was blindsided.

But if Sanchez “crumbled,” as one witness said, it could show that Sanchez was badly injured and could have acted reflexively when he fired. But another witness, according to a police detective who testified, told her that Sanchez was able to put down his infant son before falling.

That witness told Detective Lisa Larios that Kenneth French walked over to Sanchez in the span of four to five seconds and punched him, walked away and stood facing Sanchez, his fists clinched, before Sanchez shot him dead.

One witness, Diane Bawic, 24, told Schwartz that Sanchez was on the floor for 10 seconds and possibly unconscious before awakening and firing. But then she told Deputy Attorney General Mike Murphy that she had informed police that Sanchez was on the floor only one second. Then she changed that testimony to five to 10 seconds.

Another witness, Regina Boladian, 72, said she handed out samples first to the Frenches and then to the Sanchezes before Kenneth French slipped in behind his parents, walked over to Sanchez and punched him in the right temple. He fell straight down, she said.

Boladian acknowledged being nervous about testifying.

“I hope this is the last question,” she said wearily at one point. “I want to go home.”

The testimony concluded with Corona police Cpl. Robert Slane, the first officer to arrive after 911 calls. He entered to find Sanchez flat on his back in the deli. In Slane’s body-worn camera video, Sanchez says he thought he had been shot and that his head hurt.

“Where is the shooter?” Slane says in the video. “That guy,” Sanchez replies, pointing toward Kenneth French, who lay dead in a pool of blood — an image that caused a relative in the courtroom to break down.

An off-duty sheriff’s deputy then tells Corona police that it was Sanchez who fired. Sanchez then acknowledges that fact and says he saw “a blast,” saw French “hunkered down” and possibly “still armed,” so he fired. The parents, Sanchez says, “may have gotten in the way.”

The LAPD later fired Sanchez. In a civil case, a federal jury in Riverside in October awarded $17 million to Kenneth French’s estate and his parents.