A dozen people were inside the restaurant when the violence erupted at around 3:45 p.m. right outside the entrance to the establishment.
The two were involved in a violent physical struggle, as the man pummeled the officer to the ground. The officer shot once at close range, killing the man.
The officer, a 10-year-veteran of the Gardena Police Department, was hospitalized with a broken rib, facial lacerations and a possibly broken jaw.
Witnesses said that the suspect was acting strange and talking to himself. They also said that the suspect attacked the officer for no reason.
"I saw the undercover police struggling with the other individual and they were like horse playing and fighting," said witness Xavier Flores. "All of a sudden, the guy that got shot pushed the policeman against the wall of glass, and that's when we heard the bump and we all turned our heads around and we heard the shot. It was only one shot."
The suspect was pronounced dead at the hospital. Investigators say that at this point, they have no idea what set him off.
"He is familiar to law enforcement. He has had previous encounters, and based on those numerous encounters, we're certainly not ruling out the fact that narcotics may have been a factor in this," said Martinez.
It is unknown whether the officer's daughter witnessed the struggle and the shooting. She was not injured in the incident and is with family.