Authorities are searching for a man accused of shooting and killing a fellow gang member who helped him flee from a quadruple shooting in Gardena that left a woman dead and three others hospitalized Tuesday morning.

The incident began about 4 a.m. when the shooter, the shooter’s friend, and a woman later identified as the friend’s wife were partying with some other friends at a trailer park in Gardena, according to Los Angeles County Sheriff’s Department Lt. John Corina.

After becoming “upset for unknown reasons,” the man opened fire on the gathering, in the area of West 135th Street and Budlong Avenue, a sheriff’s news release stated.

“He ends up shooting three people over there. … I think they’re all women,” Corina said.

Authorities later confirmed the gunman — who has not been identified — ultimately shot five people, two males and three women. Four were shot at the trailer park:

• 28-year-old Dolores Sanchez, who was pronounced dead at the scene;
• a 23-year-old pregnant Hispanic woman, believed to be the shooter’s girlfriend, who was hospitalized;
• a 24-year-old woman who was hospitalized, treated and released; and
• a 37-year-old Hispanic man who was transported to a local hospital and is in serious condition.

The pregnant girlfriend and her unborn child are expected to survive, the Sheriff’s Department said.

A GoFundMe campaign created to raise funds for Sanchez’s memorial describes her as a “fun loving individual” who “didn’t deserve to Be taken So soon.” She is survived by both parents, two sisters and a brother, the page said.

After the shooting, the gunman had a husband and wife, who had been at the gathering, drive him away, authorities said.

“I don’t think the victim wanted to cooperate,” but he was pretty much forced to, Corina said.

When the vehicle the trio was in arrived at the Martin Luther King Jr. Boulevard onramp to the southbound 710 Freeway in Lynwood, the gunman asked his friend to pull over and then fatally shot him, Corina said.

He dragged his friend’s body out of the vehicle and also attempted to kill the wife, but his gun malfunctioned, authorities said.

“He wasn’t able to kill her so he got frustrated and left,” Corina said. “She’s lucky to be alive.”

Investigators arrived about 4:30 a.m. to find the woman still at the scene with her slain husband. A weapon was found at the scene.

The husband killed was later identified as 28-year-old Francisco Rafael Montes of Gardena.

The shooter had fled in his friend’s vehicle and authorities are trying to track him down. The car is described as a black Kia Soul.

The suspect is a 25-year-old Hispanic man who is a documented gang member, according to Corina.

“He’s been in and out of prison, he’s got a pretty lengthy, pretty violent rap sheet,” the lieutenant said. “The friend he killed was a fellow gang member.”

Investigators are trying to determine if drugs may have been involved or if the suspect was just enraged and taking it out on his friends.

“These are people he knows, these are not strangers to him. … So why he’s shooting them — we’re still trying to figure it out,” Corina said.

Later, Corina said he wasn’t sure if the incident was “drug-fueled or what the problem is,” but the suspect seemed to be “under the influence of something and not thinking clearly.”

Anyone with information is urged to call the Sheriff’s Department at 323-890-5500. Anonymous tips can also be left through Crime Stoppers by dialing 800-222-8477.

KTLA’s Melissa Pamer contributed to this article.