Three victims of a notorious Northern California serial killer and rapist said they are feeling relief after flying to California's capital city to see the alleged attacker behind bars for the first time.

They were among nearly a dozen victims and survivors who showed up for a brief, routine court hearing in the case against former police officer Joseph DeAngelo.

Former police officer Joseph James DeAngelo, 72, was arrested at his northern California home in April after a four-decade search to find a murderer and rapist dubbed the 'Golden State Killer'.

In their hunt to find the killer, US authorities theorised that he moved to Australia and raped young girls in Melbourne in the 1980s and '90s. That rapist earned the moniker Mr Cruel.

Armed with a gun, the masked attacker terrorised communities by breaking into homes while single women or couples were sleeping. He sometimes tied up the man and piled dishes on his back, then raped the woman while threatening to kill them both if the dishes tumbled.

He often took souvenirs like coins and jewellery from his victims, who ranged from 13 to 41 years old.

DeAngleo was arrested after DNA linked him to crimes attributed to the 'Golden State Killer' and he has initially been charged with four counts of murder and could face dozens more, authorities said.

Jane Carson-Sandler, who traveled from Hilton Head, South Carolina, was one of dozens of women raped by the elusive Golden State Killer.

The Associated Press does not usually identify people who say they are victims of sexual assault, but is doing so in this case because the women spoke publicly about what they said happened to them.

Carson-Sandler said she started crying and felt angry and anxious as she sat in the Sacramento County jail courtroom, until she was comforted by Debbi Domingo, whom she calls a "sister survivor."

"I hope he suffers and dies in jail," Carson-Sandler said later. "But I hope he knows that he has not won, that we have the power and control now."

She wore an orange T-shirt with a message to DeAngelo on the back: "Victim survivor thriver...See you in court."

Domingo traveled from Texas to see the man charged with killing her mother in Santa Barbara County. The women all went to lunch together after the hearing and plan to keep in touch throughout DeAngelo's prosecution.

"Seeing him locked up, that's been the goal all along, all these years that we've been searching for closure," Domingo said of DeAngelo, who looked at the judge during the two-minute hearing while keeping his back to the victims. The hearing was continued until Sept. 5.

One of the killer's youngest victims, Margaret Wardlow, said she was raped at age 13. She traveled from San Diego and called seeing DeAngelo "intense."

"It's frightening," she said. "I thought, this is the guy that came into a 13-year-old's room and raped her. How do you do that to a kid?"

Defense attorney Diane Howard declined comment after the hearing.