LONG BEACH (CBSLA) — Two men were killed and a third man was wounded in a shooting in a Long Beach sports bar early Wednesday morning, with the suspected gunman among the dead after a responding police officer allegedly shot and killed him.

At approximately 12:20 a.m., shots rang out at the Bottoms Up Tavern, located at 1739 E. Artesia Blvd.

According to Long Beach police, the suspect shot and wounded a bar employee and then appeared to exchanged gunfire with an unknown customer.

“An additional casing was found that indicates there may have been an additional shooter,” Shaunna Dandoy, spokesperson for the Long Beach police, said.

Police said the suspect then moved to another part of the bar, where he shot and killed an employee of the bar — identified as Manny Marquez — who was credited with helping to save a bartender.

“My brother grabbed the girl, and they went under the bar,” Cindy Marquez said. “And that’s when he was randomly shooting.”

A nearby patrol officer who had been flagged down by neighbors responded to the bar, confronted the gunman and then opened fire on him, police said, killing him. SWAT teams then swarmed the bar.

“An officer was on patrol when he was flagged down to the report of a shooting inside of a business,” Dandoy said. “While on scene, the officer did hear shots being fired inside of the business. When the officer engaged the suspect, an officer-involved shooting occurred.”

When SWAT entered the bar, they found two men dead, including the suspect who was discovered with a gun in his hand.

The employee who was wounded was able to escape by running out of the bar. He was later taken by ambulance to a hospital with a gunshot wound to his upper torso. He was expected to survive, police said.

Witnesses said mayhem ensued after the initial shots rang out, with people running for cover and hiding in bathrooms and the storeroom.

“I heard what sounded like to me as firecrackers,” witness Zach Cortz said. “Everybody ran out. I stood in my spot. I thought everybody is overreacting, it’s just firecrackers. And I see a guy in the back just kicking a door, it’s a back door where the kegs are stored. He’s kicking it, and I see him holding a revolver. And I see him shoot in my direction. And at that time I ran out of there.”

Police still do not have the identity of the customer who was said to have exchanged gunfire with the suspect. The additional casing that was found did not match the gun of the suspect or the police officer, and the owner of the business said an unknown man ran into the bar in an attempt to stop the shooting, but ran out before talking to police.

No officers were hurt. It’s unclear what motivated the shooting, but staff at the bar said the man was there for several hours Tuesday night before he opened fire.

There have been no arrests at this time. The Los Angeles County District Attorney’s Office was assisting with the investigation, as it does for all officer-involved shootings.