Woman celebrating birthday among 4 dead in 'targeted ambush' on Los Angeles-area home

"We will find you," the mayor said in a message to the attackers.

A woman celebrating her 20th birthday and her sister were among four people killed when multiple gunmen opened fire on a short-term rental home in Southern California on Sunday in what officials said appeared to be a gang-related "targeted ambush."

Breahna Stines and her sister, Marneysha Hamilton, 25, were identified by relatives and friends as being among those slain in the quadruple homicide in Inglewood, according to ABC station KABC in Los Angeles. Two men, whose names have not been released, were also killed in the attack and another man was critically wounded, authorities said.

No arrests have been made.

Family members said Stines, Hamilton and others at the home were from out of town and had rented the residence for a party to celebrate Steins' birthday.

"They were kids living life, just trying to have fun, celebrating life," a friend, who would only give her name as Bre, told KABC of the sisters as a makeshift memorial grew outside the scene of the crime.

The shooting erupted at about 1:30 a.m. PT in a residential neighborhood of Inglewood, about 10 miles southwest of downtown Los Angeles, according to the Los Angeles County Fire Department.

Three of the shooting victims were pronounced dead at the scene, fire department officials said. A fourth victim died en route to a Ronald Reagan UCLA Medical Center, fire officials said.

"These are sociopathic killers that have to be sequestered from society," James Butts, the mayor of Inglewood, said of the gunmen during a news conference Sunday.

The sole survivor is in critical condition at a hospital.

" ... the targeted nature of this crime, the weapons used and statements uttered before the shooting by the suspects indicate that this crime was indeed gang-related," Butts said in his statement without elaborating on what the suspects shouted before opening fire.

Numerous shell casings collected by investigators outside the home indicate that multiple shooters were involved in what Butts described as a "targeted ambush."

"The shell casing evidence indicates that at least one of the weapons was an assault rifle," Butts said, adding that one or more handguns were also used in the attack.

He said the number of shooting victims was the most in a single incident in Inglewood since the 1990s.

A motive for the shooting remains under investigation.

Butts said his message to the shooters is to "turn yourselves in."

"We will find you," Butts said, "and we will prosecute you."