A family member of the man killed by a police officer on duty at a California company Costco described his cousin as being "mentally retarded" and a "nice giant" .
Kenneth French, 32, was non-verbal, nonviolent and had never met the police, said his cousin Rick Shureih on Sunday during a phone interview.
Shurieh said he was not sure if his cousin had been diagnosed "completely" yet, but knew that French was on medication.
"His motor skills are good. it's just something [is] "He was never violent with any of us, so we do not know how it escalated."
He added that the other two people injured in the shootings were the parents and guardians of the French child, Russell and Paola French. They were in critical condition after Friday's shooting and Shurieh said that they remained hospitalized on Sunday.
Police in the city of Corona, 47 km from Los Angeles, said Frenchmen "attacked" the policeman on "unprovoked" leave at a Costco store.
The officer, who was not identified, was holding a young child and shopping with his family, police said.
French was declared dead on the scene.
Additional details about the shooting were not revealed and Shureih said that Mr. French's relatives did not really know what led to the confrontation.
"I could imagine him hitting someone by accident and not excusing himself," he said.
Three agencies were conducting shooting investigations: the Los Angeles Police Department, the Riverside District Attorney's Office and the Corona Police Department, the Associated Press reported.
LAPD policies allow officers on leave to carry concealed weapons, according to the PA. Joseph Giacalone, a professor at the John Jay Criminal Justice College, told the press service that it was legitimate for an officer to use lethal force in an overcrowded place if the attacker had a weapon.
"If the guy took out a pocket knife and approached it, the game is over," said Giacalone.
Tobias Kouroubacalis, spokesman for the Corona police, said Friday that the officer's weapon "was the only weapon involved in the incident".