Police and Santa Ana city officials said Friday they don't believe the slaying of Kim Pham outside a local nightclub was a hate crime.
The mayor of the predominantly Latino city urged Vietnamese American residents to remain calm.
"We don't see this as a hate or gang crime," said Mayor Miguel Pulido, who added that he considers the altercation to be "an isolated incident."
Police have arrested a second woman and are looking for a third in connection with Pham's death.
The latest arrest capped a frustrating week for police as they tried to coax reluctant witnesses to come forward and appealed for videos that bystanders took of the incident.
The 27-year-old Santa Ana resident arrested Friday is one of three women suspected in the melee, which has captured national attention and forced civic leaders to defend the city's historic downtown as a safe area.
Pham, 23, of Huntington Beach was removed from life support three days after the Saturday morning beating. Coroner's officials concluded her death was due to complications from blunt-force trauma to the head.
Carlos Rojas, Santa Ana's interim police chief, declined to release the name of the most recent arrestee, citing the ongoing investigation. Police did, however, release a photo of the third woman being sought.
Vanesa Tapia Zavala, a 25-year-old mother and Santa Ana resident, pleaded not guilty to murder Wednesday. She is being held on $1-million bail.
Details of what exactly occurred that night have remained murky. Police said Pham and a group of friends were entering The Crosby restaurant and nightclub as a group of five people were leaving.
As they crossed paths, there was some sort of physical contact that led to an argument and later a fight, Rojas said.
"Three people at various times, depending on what video you look at, were involved physically with Ms. Pham," Rojas said. "While there was a physical altercation, we don't know what precipitated it."
One of Pham's friends, who was not at the nightclub, said the argument may have started after she accidentally walked into a group while a photo was being taken.
But defense attorney Michael Molfetta, who said he was representing a potential suspect in the case but didn't identify which one, said the dispute started after one of Zavala's friends inadvertently bumped into Pham. He said Pham threw the first punch.
Initially police said they were looking for three women and two men, but Rojas said Friday the men are no longer considered suspects.
Detectives have reviewed at least three videos of the fight and determined that there was a simultaneous all-male brawl on the sidewalk, Rojas said. There is no evidence that a man hit Pham.
"It was a very chaotic scene," said Rojas, who estimated there were more than 50 people outside the club. "It's difficult to pinpoint who was doing what or who was trying to break up a fight, but it appears to me that one security guard was trying to separate people."
The violence has also sparked discussions about safety in Santa Ana's downtown, which has gained popularity as a destination with the arrival of new restaurants and bars.
In addition to increasing police presence in the area, the City Council this week said it would look into reactivating a downtown substation and installing surveillance cameras.
"We don't want to do all those things in reaction to this incident," said Councilman Vincent Sarmiento. "But to make sure downtown continues to flourish and remains a safe place for those who come and visit."