The incident began around 5 p.m. Sunday when Monterey Park officers arrived at an apartment building at 111 East Newmark Avenue. They found a man who had been stabbed, possibly following a traffic conflict.
A witness saw two men jump out of their cars and get into an argument.
"All of a sudden I just heard one big shouting," said witness Betty Hau. "I said it must be a fight. Then all of a sudden I saw the bigger guy attack this young little guy."
Hau said the suspect went inside the apartment building. Authorities said when police arrived, he came out shooting.
"It turned into a running gun battle," said Capt. Eugene Harris from Monterey Park police. "With the suspect running away from the location and the officers following him. That is when the suspect was shot. Somewhere in that exchange the officer was shot."
"Then I heard a gunfire exchange, at least 10 to 20 bullets," said Hau. "I was across the street trying to run away from the other side."
A SWAT team and officers from several agencies went yard to yard searching for a second suspect seen running from the area.
"It's a very small methodical process," said Harris. "A lot of agencies, a lot of officers, K-9 assets are being used. So there's a lot that we are doing."
The apartment building will remain closed as the investigation continues. Authorities said they have recovered a gun believed to be used by the suspect who wounded the officer, and then was shot and killed at the scene.
The three victims were rushed to Los Angeles County-USC Medical Center and are listed in stable condition.
It is especially amazing for that officer. Authorities said Officer Gilbert Alvarez just narrowly missed being shot in the head.
"He has a grazed gunshot wound to the upper portion of his head," said Harris. "And a large contusion on the back of his head that he suffered from the fall during the gun fight."
Investigators said the 45-year-old has his family by his side and is being kept for observation. The male victim who was stabbed in the initial incident is listed in stable condition. The innocent civilian who was caught in the crossfire and shot in the leg is also in stable condition.
Alvarez is a veteran officer with Monterey Park Police. He is expected to be released from the hospital Monday.