THE Golden State Killer didn’t simply enjoy the rapes and murders he tallied during a terrifying decades-long crime spree.

He revelled in the lead-up. He stalked homes, knew his victims and tormented them. He phoned police and called them “dumb f***ers”, promising he would attack again. Then he followed through on sick threats.

A day after police in the Sacramento area announced they had arrested 72-year-old Joseph James DeAngelo in relation to 12 murders and as many as 45 rapes during the 1970s and ’80s, 911 audio of the killer’s voice surfaced.

In one tape, a man police believe to be Mr DeAngelo phoned a female victim. It was 1977, and he had not yet graduated from rape to murder.

“Gonna kill you,” he said between fits of loud breathing. “Gonna kill you. Gonna kill you. B**ch. B**ch. Whore.”

In another phone call to police, he told them: “It’s me, the East Area rapist, you dumb f***ers. I’m gonna f**k again tonight.”

The phone calls are an insight into the mind of a man who evaded police for more than 40 years. He knew how to get away with it because he once was an officer himself, police say.

Their suspect, Mr DeAngelo, was fired from the Auburn Police Department, two hours north of Sacramento, in 1979 after he was arrested for stealing a can of dog repellent and a hammer from a chemist.

The “quiet” grandpa from Citrus Heights, California, carried out his attacks in sadistic fashion. His most depraved tactic included tying up men and piling dishes on their backs while he raped their partners. He told them that if the plates tumbled to the ground, he would kill them both.

Police say he entered homes up and down the coast wearing ski masks and armed with a gun and a knife. He woke his victims by shining a flashlight in their eyes and spoke through gritted teeth to disguise his voice.

He told one woman during her rape: “You’ll be silent forever, and I’ll be gone in the dark”. The threat inspired the book I’ll Be Gone In The Dark by Michelle McNamara that police say played a role in helping them track down the man suspected of being the serial rapist and killer.

Mr DeAngelo, a Vietnam War veteran, was arrested by police at his home in Citrus Heights, the same Sacramento suburb where rapes were carried out on September 4, 1976 and October 5, 1976 when he was employed by the Auburn Police Department.

Police used DNA to finally track him down and tie him to the crimes but refused to give specifics about how it was collected or matched to the suspect. They admitted that despite decades of work, Mr DeAngelo’s name had not been on authorities’ radar before last week.

“We knew we were looking for a needle in a haystack, but we also knew that needle was there,” District Attorney Anne Marie Schubert said.

“We found the needle in the haystack ... the answer was always going to be in the DNA.”

Jane Carson-Sandler, who was sexually assaulted in California in 1976 by a man believed to be the so-called “East Area Rapist”, said she received an email on Wednesday from a retired detective who worked on the case telling her they have identified the suspected rapist and he’s in custody.

“I have just been overjoyed, ecstatic. It’s an emotional rollercoaster right now,” Carson-Sandler, who now lives near Hilton Head, South Carolina, told The Associated Press in a telephone interview.

“I feel like I’m in the middle of a dream and I’m going to wake up and it’s not going to be true. It’s just so nice to have closure and to know he’s in jail.”