Riverside County prosecutors had decided not to charge Officer Salvador Sanchez for the June 14 incident, in which he shot 32-year-old Kenneth French and his parents while they were shopping.
French, described as developmentally disabled by his family, was killed in the shooting. His parents, Russell and Paola French, were wounded by gunfire and hospitalized.
Sanchez's attorney has said the incident began when the off-duty policeman was assaulted while holding his toddler son, and contended that Sanchez opened fire after being knocked to the floor.
The matter has not been turned over to Chief Michel Moore who will decide if further action, including disciplinary, will be handed down. He has ordered a complaint investigation to be completed.
"Regardless of the outcome of this next chapter, I express my profound regret for what occurred to the French family and loved ones," Moore said in a written statement. "The decisions and actions of this officer cannot be justified and are inconsistent with the Department's Core values, training and expectations of every member of this organization."
French's family filed a civil rights lawsuit back in January.